What you see	What it means
`401 Authorization header is required`	The client isn't sending the token. Check the header made it into the config.
`401 Access token has expired`	Tokens last an hour. Mint a new one.
`401 Access token has been revoked`	The API client was revoked on the API page.
`403 ... missing required scope(s)`	The token wasn't granted that scope. Create a client that has it.
`401 Company has outstanding charges`	Billing is locked; the whole API is closed until it's settled.
`429 Too Many Requests`	The company's API rate limit. Wait for the window named in the response.
A tool you expected isn't listed	The token lacks its scope — `whoami` names the ones it has.

Anything else comes straight from the underlying API endpoint, with its status code, so it means what it means in the API reference.

Errors