Issue

Lync Mobile Client won’t sign in.
Mobile client logs contain the error E_AuthError E2-3-2
Tests from testconnectivity.microsoft.com are successful.

NOTE
If the tests from testconnectivity.microsoft.com are unsuccessful then you may need to recheck the user credentials

Reviewing the logs from the mobile device you find the following error messages:-

• 401 – Unauthorized: Access is denied due to invalid credentials.
• You do not have permission to view this directory or page using the credentials that you supplied.
• Received webticket resposne with status E_AuthError (E2-3-2)
• Mapping error code = 0x22030002
• Mapped error message is ‘We can’t sign you in. Please check your account info and try again.

Clearly there is some issue with your credentials.

If you go back to the testconnectivity.microsoft.com  site you will recall being prompted for Domain\User Name (or UPN)

Cause and Resolution

The issue is that the mobile client does not require or prompt the user for the Domain\User Name (or UPN). The field is actually a little hidden and thus often overlooked. You can find it in Show Advanced Options.

TIP

If you enable UPN Naming for the user account and the SIP address is also the UPN address then the mobile user does not need to provide the User Name in Advanced options.