When attempting Integrated logon, the following error is thrown: 401.2: Unauthorised.
The authentication methods that were tried failed for some reason. This could be because they were disabled, were attempted through a proxy (in the case of NTLM), or, in Windows Server 2008, the authentication methods set in IIS are in the wrong order in Authentication>Windows Authentication:Providers.
It shouldn't matter what order the authentication methods are in, and by default, Negotiate comes first, then NTLM. However there have been occasions where changing the order has resolved this issue, so try setting NTLM first, then Negotiate.