Claude API 401 (authentication_error)
Is there an outage right now?
Claude API official status is operational. If this error persists, it is likely an implementation or environment issue on your side.
Updated: Jul 21, 2026, 8:40 PM UTC
View Claude API status →What this error means
401 means authentication failed: invalid/expired/missing key or bad x-api-key header.
Common causes
- •Wrong/expired API key
- •Missing/malformed x-api-key header
- •Env var not loaded
- •Key/org mismatch
How to fix
- 1.Reissue the key in Console and set via env
- 2.Check `x-api-key` and `anthropic-version` headers
- 3.Read key from env, not hardcoded
- 4.Use the correct org/workspace
When waiting helps (and when it won't)
Config issue—waiting will not fix it. Re-check key and headers.
Alternatives when Claude API is down
Related errors
FAQ
What is 401 authentication_error?
401 means authentication failed: invalid/expired/missing key or bad x-api-key header.
How do I fix 401 authentication_error?
Reissue the key in Console and set via env / Check `x-api-key` and `anthropic-version` headers / Read key from env, not hardcoded / Use the correct org/workspace