Error / Message
Invalid API key or authentication error
Claude Code's credentials — whether from a login flow or an API key — have expired, been revoked, or aren't configured, and it can't authenticate.
This is usually resolved by simply logging in again rather than deep debugging — credentials expiring naturally over time is normal and expected, not a sign of misconfiguration.
If you're using an API key directly rather than the standard login flow, double-check it's the current one and hasn't been rotated or revoked on the account it belongs to.
Persisting past a fresh login is the signal something else is wrong — worth checking account status and any organization-level access restrictions at that point.
Log in again to refresh your credentialsFrequently asked questions
What does "Invalid API key or authentication error" mean in Claude Code?
Claude Code's credentials — whether from a login flow or an API key — have expired, been revoked, or aren't configured, and it can't authenticate.
How do I fix it?
Try: Log in again to refresh your credentials
Is this something to worry about?
Persisting past a fresh login is the signal something else is wrong — worth checking account status and any organization-level access restrictions at that point.
Is this covered in the Claude Code Toolkit?
Yes — Invalid API key or authentication error and patterns like it are part of the full command, hook, and template pack included with a Claude Code Toolkit subscription.
Want the full command, hook, and template pack?
This is one pattern out of the full Claude Code Toolkit — subscribe for the complete set, plus everything we add going forward.
Subscribe to the toolkit — $79/mo