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Developer troubleshooting database and error fix guide
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High-value troubleshooting hubs
Start with the strongest revenue-focused hubs for API failures, AI coding assistant problems, CI/CD breakage, Docker issues, deployment failures, Cloudflare errors, LiteLLM routing, and Ollama model runtime errors.
Recently updated source-backed errors
These pages include public source URLs in the imported page body. They still require local verification, but they are stronger starting points than generic checklists.
- Google AI Studio Quota Exceeded Despite Paid Tier 1 — Free Tier Quota Bug (June 11, 2026)
- Error 522 Connection Timed Out origin server behind Cloudflare Workers returning connection timeout (June 10, 2026)
- Claude Code OAuth DNS Resolution Failure — auth.anthropic.com ENOTFOUND (June 10, 2026)
- Docker 'Bind for 0.0.0.0:PORT failed: port is already allocated' (June 10, 2026)
- GitHub Actions Permission Denied EACCES — Resource Not Accessible by Integration (June 10, 2026)
- GitHub Copilot CLI Auth Swallows REST Quota Errors — Session Was Not Created (June 10, 2026)
- LiteLLM Connection Refused Error — Proxy Misconfiguration (June 10, 2026)
- OpenAI API 429 Rate Limit Exceeded — Production Impact (June 10, 2026)
How we build troubleshooting guidance
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Pages should start from a real error signature, category, technology, common causes, and update fields.
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Outdated or unsupported claims can be reported through the contact page with the page URL and public source.
Read the editorial methodology, source policy, and troubleshooting methodology.
What to check before applying a fix
- Confirm the exact error signature and the smallest command, request, CI job, or editor action that reproduces it.
- Record versions for the runtime, package manager, SDK, CLI, provider, operating system, and deployment target.
- Redact secrets before sharing logs, issue links, screenshots, stack traces, or request payloads.
- Test one change at a time in local or staging before applying it to production.
Common error categories
Use these crawlable category hubs to move from a broad failure mode to specific error signatures and fixes.
Recently trending developer errors
Vercel Build Failed — Node Version & Missing Env Var Drift
Fix Vercel deployment build failures caused by environment drift (Node version mismatch, missing build-time env vars like NEXT_PUBLIC_*), TypeScript stricter compilation, or OOM conditions Includes evidence for Vercel troubleshooting demand.
Cannot find module OR "Module not found" OR Process completed with exit code 1 OR Vercel build failed despite local npm run build being green Docker 'Bind for 0.0.0.0:PORT failed: port is already allocated'
Resolve Docker Compose or docker run port binding conflicts where host port is already occupied by another container or host process Includes evidence for Docker troubleshooting demand.
ERROR: Bind for 0.0.0.0:5001 failed: port is already allocated OR bind: address already in use GitHub Actions Permission Denied EACCES — Resource Not Accessible by Integration
Fix GitHub Actions workflow permission errors including GITHUB_TOKEN scope issues, fork PR restrictions, and runner filesystem ownership conflicts from root vs non-root step runs Includes evidence for GitHub Actions troubleshooting demand.
Error: HttpError: Resource not accessible by integration OR remote: Permission to user/repo.git denied to github-actions[bot] OR Error: EACCES: permission denied, open '/home/runner/.npm/_cacache/...' OpenAI API 429 Rate Limit Exceeded — Production Impact
Fix OpenAI 429 rate limit error by understanding RPM/TPM dimensions and configuring proper retry/backoff strategy Includes evidence for OpenAI API troubleshooting demand.
Rate limit reached for gpt-3.5-turbo in organization org-exampleorgid123 on tokens per min. Limit: 10000.000000 / min. Current: 10020.000000 / min. OpenAI API Quota Exceeded Despite Showing Available Balance — Free Credit Mismatch Bug
Fix OpenAI API 429 quota errors when the account balance page shows available free credits that are actually expired or inactive — users cannot tell the difference between balance display and actual usable spend. Includes evidence for OpenAI API troubleshooting demand.
RateLimitError: You exceeded your current quota, please check your plan and billing details — even with free credit grants displayed as available GitHub Copilot CLI Auth Swallows REST Quota Errors — Session Was Not Created
Diagnose and fix GitHub Copilot CLI authentication failures caused by silent swallowing of REST quota exceeded and rate limit errors during token validation phase Includes evidence for GitHub Copilot troubleshooting demand.
Session was not created with authentication info or custom provider (root cause: CLI auth flow silently swallows REST quota/rate-limit errors during token validation) Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue
Next.js app builds successfully on developer's machine (Windows/macOS) but fails on Vercel deploy with case-sensitivity module not found errors. File paths look correct but Vercel's Linux filesystem is case-sensitive. Includes evidence for Vercel troubleshooting demand.
ModuleNotFoundError: Module not found: Can't resolve '@/components/forms/RegisterForm' | Build failed because of webpack errors OpenAI API 429 returns opaque error without rate-limit header details
User gets a 429 rate limit error from OpenAI but cannot see the actual rate-limit headers (x-ratelimit-remaining, x-ratelimit-reset) to diagnose whether they are truly over the limit or hitting a false-positive throttling. Includes evidence for OpenAI API troubleshooting demand.
Error code: 429 - {'error': {'code': 'rate_limit_error', 'message': 'This request would exceed the rate limit for your organization...', 'type': 'invalid_request_error'}} Google AI Studio Quota Exceeded Despite Paid Tier 1 — Free Tier Quota Bug
Fix quota exceeded error on paid Gemini API tier — developers have active billing and minimal usage but are stuck on free-tier quotas Includes evidence for Google Gemini API troubleshooting demand.
"Quota exceeded. Please try again later." on Google AI Studio despite being a paid Tier 1 project with minimal usage and active billing. Docker EACCES Permission Denied on npm Install Global and CLI Scripts
Fix Docker EACCES permission denied errors when installing global npm packages or running build scripts inside containers Includes evidence for Docker troubleshooting demand.
EACCES: permission denied — mkdir /usr/local/lib/node_modules/.npm/_cacache/tmp or node_modules during npm install global package in Docker/container Error 522 Connection Timed Out origin server behind Cloudflare Workers returning connection timeout
Web developers whose sites are protected by Cloudflare experience intermittent 522 errors preventing visitors from reaching their origin servers; need diagnostic steps and resolution methods Includes evidence for Cloudflare troubleshooting demand.
Error 522 Origin connection timed out — Cloudflare Workers unable to reach upstream origin LiteLLM 1.82.1 OpenRouter Model IDs No Longer Working
After upgrading to LiteLLM 1.82.1, previously working OpenRouter model IDs throw 404 errors. Users proxying through LiteLLM proxy lose access to OpenRouter models and need quick workaround to restore routing to healthy deployments. Includes evidence for LiteLLM troubleshooting demand.
litellm.CallFailed: Error code: 404 — OpenRouter model IDs stopped working after LiteLLM upgrade to v1.82.1 Most searched fixes
- Vercel Build Failed — Node Version & Missing Env Var Drift
- OpenAI Codex Provider Returns Usage Limit Reached Error (Subscription Quota)
- Dify Cloud quota for OpenAI returns insufficient_quota errors after billing setup
- GitHub Copilot CLI Auth Swallows REST Quota Errors — Session Was Not Created
- Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue
- GitHub Copilot Auth Token Expired — "Timed Out Waiting for Authentication Provider to Register"
- Kubernetes ImagePullBackOff — unable to pull container image from private registry
- OpenAI API Rate Limit 429 — TPM/RPM Limits Exceeded in Production
- Cursor Error Troubleshooting Guide: 10+ Solutions for API Key, Model, Network Issues
- Docker 'Bind for 0.0.0.0:PORT failed: port is already allocated'
- GitHub Actions Permission Denied EACCES — Resource Not Accessible by Integration
- OpenAI API 429 Rate Limit Exceeded — Production Impact
Common API failures
Authentication failed, rate limit, quota exceeded, model not found, context length, timeout, and provider routing errors.
- OpenAI API 429 Rate Limit Exceeded — Production Impact
- OpenAI API Quota Exceeded Despite Showing Available Balance — Free Credit Mismatch Bug
- OpenAI API 429 returns opaque error without rate-limit header details
- LiteLLM 1.82.1 OpenRouter Model IDs No Longer Working
- OpenAI API RateLimitError Despite Having Credits — Billing vs Quota Confusion
- OpenAI API 429 Even With Available Credits — Prepaid Grant Exhaustion Causes Quota Error
- OpenAI API Rate Limit 429 — TPM/RPM Limits Exceeded in Production
- OpenAI Codex Provider Returns Usage Limit Reached Error (Subscription Quota)
- LiteLLM Connection Refused Error — Proxy Misconfiguration
- LiteLLM Proxy Authentication Failed — 'failed-to-connect-to-db' Bypass Vulnerability (CVE-2026-42208)
Deployment troubleshooting
Vercel build failed, GitHub Actions failed, permission denied, missing modules, SSL handshake, DNS, and cloud origin failures.
- Vercel Build Failed — Node Version & Missing Env Var Drift
- GitHub Actions Permission Denied EACCES — Resource Not Accessible by Integration
- Vercel Build Succeeds Locally But ModuleNotFoundError on Deploy — Case Sensitivity Issue
- Google AI Studio Quota Exceeded Despite Paid Tier 1 — Free Tier Quota Bug
- Error 522 Connection Timed Out origin server behind Cloudflare Workers returning connection timeout
- Azure Pipelines service connection authorization error AADSTS7000222 client secret expired
- GitHub Actions Checkout Fails: repository not found / terminal prompts disabled
- Vercel Deploy Module Not Found Due to Case-Sensitive Filesystem on Windows
- Vercel Build Fails with Module Not Found Due to File Case Sensitivity Mismatch
- GitHub Actions Permission Denied When Pushing to Repo — GITHUB_TOKEN vs PAT Mismatch
AI coding assistant errors
Claude Code, Cursor, GitHub Copilot, OpenRouter, Ollama, LiteLLM, and model-routing failures in coding workflows.
- GitHub Copilot CLI Auth Swallows REST Quota Errors — Session Was Not Created
- GitHub Copilot Auth Token Expired — "Timed Out Waiting for Authentication Provider to Register"
- Cursor Error Troubleshooting Guide: 10+ Solutions for API Key, Model, Network Issues
- GitHub Copilot Pro+ user weekly rate limit blocks premium requests permanently
- Claude Code OAuth DNS Resolution Failure — auth.anthropic.com ENOTFOUND
- Fix: `ECONNREFUSED` When a Local MCP Server Starts Before the Client Is Ready — Claude Code / Cursor
- OpenRouter Auth Token Expires Mid-Session — AADSTS90009 After ~60 Min Silent Refresh
- LangChain RateLimitError wrapping OpenAI 429 — excessive API calls per minute exceeded
- GitHub Copilot Paid User Stuck on Persistent Global Rate Limit Despite Low Usage
- Claude Code MCP Server Authorization Failed — OAuth & Keychain Fixes
Latest high-value pages
Google AI Studio Quota Exceeded Despite Paid Tier 1 — Free Tier Quota Bug
Fix quota exceeded error on paid Gemini API tier — developers have active billing and minimal usage but are stuck on free-tier quotas Includes evidence for Google Gemini API troubleshooting demand.
"Quota exceeded. Please try again later." on Google AI Studio despite being a paid Tier 1 project with minimal usage and active billing. Error 522 Connection Timed Out origin server behind Cloudflare Workers returning connection timeout
Web developers whose sites are protected by Cloudflare experience intermittent 522 errors preventing visitors from reaching their origin servers; need diagnostic steps and resolution methods Includes evidence for Cloudflare troubleshooting demand.
Error 522 Origin connection timed out — Cloudflare Workers unable to reach upstream origin Claude Code OAuth DNS Resolution Failure — auth.anthropic.com ENOTFOUND
Fix Claude Code OAuth login failures caused by DNS resolution failure of auth.anthropic.com Includes evidence for Claude Code troubleshooting demand.
getaddrinfo ENOTFOUND auth.anthropic.com — Claude Code OAuth login fails with timeout; auth.anthropic.com does not resolve via DNS, making authentication impossible Docker 'Bind for 0.0.0.0:PORT failed: port is already allocated'
Resolve Docker Compose or docker run port binding conflicts where host port is already occupied by another container or host process Includes evidence for Docker troubleshooting demand.
ERROR: Bind for 0.0.0.0:5001 failed: port is already allocated OR bind: address already in use GitHub Actions Permission Denied EACCES — Resource Not Accessible by Integration
Fix GitHub Actions workflow permission errors including GITHUB_TOKEN scope issues, fork PR restrictions, and runner filesystem ownership conflicts from root vs non-root step runs Includes evidence for GitHub Actions troubleshooting demand.
Error: HttpError: Resource not accessible by integration OR remote: Permission to user/repo.git denied to github-actions[bot] OR Error: EACCES: permission denied, open '/home/runner/.npm/_cacache/...' GitHub Copilot CLI Auth Swallows REST Quota Errors — Session Was Not Created
Diagnose and fix GitHub Copilot CLI authentication failures caused by silent swallowing of REST quota exceeded and rate limit errors during token validation phase Includes evidence for GitHub Copilot troubleshooting demand.
Session was not created with authentication info or custom provider (root cause: CLI auth flow silently swallows REST quota/rate-limit errors during token validation) LiteLLM Connection Refused Error — Proxy Misconfiguration
Fix LiteLLM proxy ConnectionRefusedError by verifying proxy process is running on expected host:port, resolving Docker network isolation, unsetting conflicting LITELLM_PORT env variable Includes evidence for LiteLLM troubleshooting demand.
litellm.llms.custom_httpx.http_handler.HTTPHandler.post: Connection refused OR httpx.ConnectError: [Errno 111] Connection refused OpenAI API 429 Rate Limit Exceeded — Production Impact
Fix OpenAI 429 rate limit error by understanding RPM/TPM dimensions and configuring proper retry/backoff strategy Includes evidence for OpenAI API troubleshooting demand.
Rate limit reached for gpt-3.5-turbo in organization org-exampleorgid123 on tokens per min. Limit: 10000.000000 / min. Current: 10020.000000 / min. Vercel Build Failed — Node Version & Missing Env Var Drift
Fix Vercel deployment build failures caused by environment drift (Node version mismatch, missing build-time env vars like NEXT_PUBLIC_*), TypeScript stricter compilation, or OOM conditions Includes evidence for Vercel troubleshooting demand.
Cannot find module OR "Module not found" OR Process completed with exit code 1 OR Vercel build failed despite local npm run build being green Fix: `ECONNREFUSED` When a Local MCP Server Starts Before the Client Is Ready — Claude Code / Cursor
User configures an MCP server in Claude Code and receives ECONNREFUSED because the server hasn't finished listening yet; needs fix for startup race condition and localhost IPv6 binding. Includes evidence for Claude Code troubleshooting demand.
Error: connect ECONNREFUSED 127.0.0.1:3000 / TCPConnectWrap.afterConnect [as oncomplete] LiteLLM 1.82.1 OpenRouter Model IDs No Longer Working
After upgrading to LiteLLM 1.82.1, previously working OpenRouter model IDs throw 404 errors. Users proxying through LiteLLM proxy lose access to OpenRouter models and need quick workaround to restore routing to healthy deployments. Includes evidence for LiteLLM troubleshooting demand.
litellm.CallFailed: Error code: 404 — OpenRouter model IDs stopped working after LiteLLM upgrade to v1.82.1 OpenRouter Auth Token Expires Mid-Session — AADSTS90009 After ~60 Min Silent Refresh
Developers using GitHub Copilot CLI via MCP sessions experience silent OAuth token expiration after ~60 minutes. The silent refresh sends outdated OAuth v1 resource format instead of v2 scope format, causing Azure AD rejection (AADSTS90009). Long-running coding sessions die unexpectedly without re-auth flow. Includes evidence for GitHub Copilot troubleshooting demand.
MCP silent token refresh sends v1 resource=<clientId> instead of v2 scope= → AADSTS90009 after ~60 min / GitHub Copilot API token expires mid-session with no proactive refresh, causing 401 errors in long-running subagents Azure Pipelines service connection authorization error AADSTS7000222 client secret expired
CI/CD pipelines fail with AADSTS7000222 when Azure AD service principal secrets expire; developers need to rotate credentials without breaking builds. Includes evidence for Azure troubleshooting demand.
AADSTS7000222: The provided client secret keys for app are expired — Azure DevOps pipeline fails to authenticate to Azure Resource Manager GCP Cloud Build 403 Permission Denied custom service account deploy failure
Deployments from Google Cloud Build to Cloud Run fail with 403 Permission Denied when using custom service accounts; the roles required extend beyond just Cloud Build and Cloud Run. Includes evidence for GCP troubleshooting demand.
403 Permission Denied on Cloud Run Deploy / Cloud Build custom service account — even with Owner role Long-running Azure Pipelines jobs lose authentication and fail at finalization
Azure Pipelines jobs that run longer than expected (e.g., compilation, testing suites) silently lose authentication mid-execution and fail at the finalization stage, requiring investigation of agent timeout and credential refresh settings. Includes evidence for Azure troubleshooting demand.
[BUG]: Long-running jobs lose authentication and fail at finalization — Azure Pipelines agent loses session token during extended execution OAuth completes but Bearer token never sent to MCP server — Claude Code needs re-authentication
Fix Claude Code MCP OAuth flow where token acquisition appears successful but the server continues requesting authentication, requiring manual restart or re-login Includes evidence for Claude Code troubleshooting demand.
Claude Code OAuth authentication completes but MCP server stays in 'Needs authentication' state; Bearer token never sent to downstream server Claude Code MCP Server Authorization Failed — OAuth & Keychain Fixes
Fix Claude Code MCP connection/auth failures caused by OAuth timeout, locked keychain, or DNS preventing auth endpoint reachability Includes evidence for Claude Code troubleshooting demand.
Authorization with the MCP server failed / Couldn't reach the MCP server — OAuth callback timeouts, macOS keychain locked, or DNS resolution blocking the Anthropic auth endpoint Docker Compose Port Is Already Allocated — Service Replica Port Conflict Fix
Fix Docker Compose 'port is already allocated' error when deploying multi-replica services; learn proper port mapping for replicated containers using service discovery instead of direct port binding Includes evidence for Docker troubleshooting demand.
port is already allocated — docker-compose fails when using replicas with explicit port mapping; listen tcp 0.0.0.0:PORT: bind: address already in use Docker Port Allocator Bug — Port Shows In Use After Container Kill Despite netstat Showing Free
Diagnose why Docker reserves port internally even after stopping/removing container; find cause of stale port reservation that persists through docker-compose down and reboot Includes evidence for Docker troubleshooting demand.
bind: address already in use — netstat -a -b -o reveals no service listening on port but Docker still refuses to bind; occurs after Docker update or container kill/cleanup cycle Claude Code Auth Failed? Fix Authentication in 5 Minutes
Claude Code 用户遇到认证失败（OAuth token 过期或 API key 无效），需要在本地开发环境或无头服务器上重新配置身份验证以恢复编码能力。 Includes evidence for Claude Code troubleshooting demand.
Authentication failed. Run `claude auth login` to authenticate. / Error: 401 - {"error":{"type":"authentication_error","message":"invalid x-api-key"}} Browse all error pages with pagination or open the latest troubleshooting archive.
Recently updated pages
- Google AI Studio Quota Exceeded Despite Paid Tier 1 — Free Tier Quota Bug (June 11, 2026)
- Error 522 Connection Timed Out origin server behind Cloudflare Workers returning connection timeout (June 10, 2026)
- Claude Code OAuth DNS Resolution Failure — auth.anthropic.com ENOTFOUND (June 10, 2026)
- Docker 'Bind for 0.0.0.0:PORT failed: port is already allocated' (June 10, 2026)
- GitHub Actions Permission Denied EACCES — Resource Not Accessible by Integration (June 10, 2026)
- GitHub Copilot CLI Auth Swallows REST Quota Errors — Session Was Not Created (June 10, 2026)
- LiteLLM Connection Refused Error — Proxy Misconfiguration (June 10, 2026)
- OpenAI API 429 Rate Limit Exceeded — Production Impact (June 10, 2026)
- Vercel Build Failed — Node Version & Missing Env Var Drift (June 10, 2026)
- Fix: `ECONNREFUSED` When a Local MCP Server Starts Before the Client Is Ready — Claude Code / Cursor (June 10, 2026)