Fault handling: GSM Authentication Unacceptable

 Symptom:

 The MS responds with an Authentication and Ciphering Failure message carrying the cause value GSM Authentication Unacceptable.

Fault Analysis:

 The authentication of the MS fails.

Cause Analysis:

 The MS supports only the authentication through the UMTS authentication set, but the core network delivers the GSM authentication set.

Solution

1. Check the MS subscription data on the HLR.
2. Restart the MS.