# 32106: SIP: Authentication Error

Log Level: ERROR

## Description

SIP authentication fails when the SIP endpoint's Authorization name and username do not match. Use the same username in the SIP endpoint and in the Credential List mapped to the SIP Domain, and make sure the password or secret matches that credential.

### Possible causes

* The SIP endpoint's Authorization name and username do not match.
* The username on the SIP endpoint does not exactly match a username in the Credential List mapped to the SIP Domain.

### Possible solutions

* Configure the SIP endpoint so the username and Authorization name match.
* Confirm the password or secret matches the Credential List entry mapped to the SIP Domain.

#### Additional resources

* [Error and Warning Dictionary](/docs/api/errors)
* [SIP Registration](/docs/voice/api/sip-registration)
* [SIP Security Best Practices](/docs/voice/api/sip-security)