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Claude Code's credentials — whether from a login flow or an API key — have expired, been revoked, or aren't configured, and it can't authenticate.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Claude Code's credentials — whether from a login flow or an API key — have expired, been revoked, or aren't configured, and it can't authenticate.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 OG Flow Code Premium Toolkit?
Yes — Invalid API key or authentication error and patterns like it are covered by the commands, and in higher tiers the specialist agents and guided skills, in OG Flow Code Premium Toolkit. Tiers start at $19.90.
Want the full command, hook, and template pack?
This is one pattern from the OG Flow Code toolkit. Choose the tier that fits your workflow, including Multi-Stack for six additional language stacks.
See pricing — from $19.90 once