Claude Code / AI Coding Tools

Claude Code Custom MCP OAuth Token Not Persisting Across Restarts

Fix Claude Code custom MCP connector failing to persist OAuth tokens across app restarts, showing 'Failed to connect' instead of reconnecting automatically Includes evidence for Claude Code troubleshooting demand.

Source-backed Last updated May 22, 2026 1 source Needs local verification

Category: AI Coding Tools
Error signature: Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect
Quick fix: Verify the account session, API key, provider settings, and environment where the failing tool is running.
Updated: May 22, 2026
Verification status: Source-backed
Evidence: 1 public source URL

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for Claude Code, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect is a Claude Code failure pattern reported for developers trying to fix claude code custom mcp connector failing to persist oauth tokens across app restarts, showing 'failed to connect' instead of reconnecting automatically. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Multiple GitHub issues confirm: custom MCP OAuth connectors in Claude Code fail to persist tokens after app restart. Issue #52564 (Apr 2026) shows Settings → Connectors silently reports 'Connected' but no tools load. The root cause is divergent token storage code paths between managed and custom connectors. Reported by 3+ independent users across Windows/macOS (Quarri, Daily Bread Agent, Quizlar servers). Severity: active regression. Maps to AI Coding Tools.

Common causes

Multiple GitHub issues confirm: custom MCP OAuth connectors in Claude Code fail to persist tokens after app restart. Issue #52564 (Apr 2026) shows Settings → Connectors silently reports 'Connected' but no tools load. The root cause is divergent token storage code paths between managed and custom connectors. Reported by 3+ independent users across Windows/macOS (Quarri, Daily Bread Agent, Quizlar servers). Severity: active regression. Maps to AI Coding Tools.

Quick fixes

Confirm the exact error signature matches Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect.
Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
Verify the account session, API key, provider settings, and environment where the failing tool is running.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect exactly before applying the quick fix.
Compare the failing environment with Claude Code versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect mean in Claude Code?

Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect indicates the workflow described by "Claude Code Custom MCP OAuth Token Not Persisting Across Restarts" failed in a AI Coding Tools context. Start by confirming the exact signature and the component that emitted it.

What should I check first for Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect?

Check whether this cause matches your environment: Multiple GitHub issues confirm: custom MCP OAuth connectors in Claude Code fail to persist tokens after app restart. Issue #52564 (Apr 2026) shows Settings → Connectors silently reports 'Connected' but no tools load. The root cause is divergent token storage code paths between managed and custom connectors. Reported by 3+ independent users across Windows/macOS (Quarri, Daily Bread Agent, Quizlar servers). Severity: active regression. Maps to AI Coding Tools.

Is the Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect guidance source-backed?

The "Claude Code Custom MCP OAuth Token Not Persisting Across Restarts" page is labeled source-backed. It has 1 public source URL from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect?

For "Claude Code Custom MCP OAuth Token Not Persisting Across Restarts", avoid applying "Verify the account session, API key, provider settings, and environment where the failing tool is running." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging Authentication successful, but server reconnection failed. You may need to manually restart Claude Code for the changes to take effect. ✗ Failed to connect?

For "Claude Code Custom MCP OAuth Token Not Persisting Across Restarts", collect the failing Claude Code command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.