Back

Definition
An authentication error occurs when a system cannot verify a user’s identity during a login or access attempt. This can happen due to incorrect credentials, expired sessions, invalid tokens, misconfigured authentication settings, or failed identity verification checks.

Why it matters
Authentication errors prevent legitimate users from accessing systems and can signal deeper security or configuration issues. Frequent authentication errors degrade user experience, increase support costs, and may indicate attempted account takeover, token misuse, or integration failures in identity systems.

Example use case
A user enters the correct username and password, but their session token has expired. The system rejects the login attempt and returns an authentication error, requiring the user to re authenticate.