Errors
session_expired
The browser session backing this request is no longer valid.
session_expired is a 401 raised on browser-authenticated requests when the signed-in session has lapsed. It does not apply to API-key calls: a machine key that fails authentication returns authentication_failed instead.
Recovery guidance
Sign in again to establish a fresh session, then repeat the request. Do not retry the original request unchanged — the credential, not the request, is what expired. If sessions expire sooner than expected for everyone in an organization, that is a configuration question rather than a client bug.