[BUG] OAuth refresh returns 400 after early 401 before local expiresAt — concurrent sessions forced to /login

What this error means

API Error: 401 Invalid authentication credentials — OAuth POST https://platform.claude.com/v1/oauth/token returns HTTP 400 during refresh after early server-side revocation, repeated /login prompts every few hours is a Claude Code failure pattern reported for developers trying to fix claude code oauth session rejection causing repeated 401 errors and forced re-login loops even before local token expiry. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Found in anthropics/claude-code#54443 (open, created 2026-04-28). Server-side early revocation causes OAuth refresh to fail with HTTP 400. Users experience repeated 401 prompts every few hours. Strongly overlaps with prior issue #52202 (early-revocation path). Maps to AI Coding Tools category per SKILL rules. High commercial value — affects paying Pro/Max users.

Common causes

• Found in anthropics/claude-code#54443 (open, created 2026-04-28). Server-side early revocation causes OAuth refresh to fail with HTTP 400. Users experience repeated 401 prompts every few hours. Strongly overlaps with prior issue #52202 (early-revocation path). Maps to AI Coding Tools category per SKILL rules. High commercial value — affects paying Pro/Max users.

Quick fixes

1. Confirm the exact error signature matches API Error: 401 Invalid authentication credentials — OAuth POST https://platform.claude.com/v1/oauth/token returns HTTP 400 during refresh after early server-side revocation, repeated /login prompts every few hours.
2. Check the Claude Code account, local tool state, and provider configuration involved in the failing workflow.
3. 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

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. 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.

Sources checked

• https://github.com/anthropics/claude-code/issues/54443

Evidence note: Found in anthropics/claude-code#54443 (open, created 2026-04-28). Server-side early revocation causes OAuth refresh to fail with HTTP 400. Users experience repeated 401 prompts every few hours. Strongly overlaps with prior issue #52202 (early-revocation path). Maps to AI Coding Tools category per SKILL rules. High commercial value — affects paying Pro/Max users.

Related errors

• AI Coding Tools

FAQ

What should I check first?

Start with the exact API Error: 401 Invalid authentication credentials — OAuth POST https://platform.claude.com/v1/oauth/token returns HTTP 400 during refresh after early server-side revocation, repeated /login prompts every few hours text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Claude Code workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without API Error: 401 Invalid authentication credentials — OAuth POST https://platform.claude.com/v1/oauth/token returns HTTP 400 during refresh after early server-side revocation, repeated /login prompts every few hours.