When you sign in to Office Communicator Web Access R2 Web Site you receive the following error.
Cannot sign in because your computer clock is not set correctly or your account is invalid. (Error Code: 0-1-492)
This issue occurs because the Service Principal Name (SPN) of the CWA site is missing.
In short the solution is usually just add a SPN to the CWAService account that matches the FQDN of the CWA Website.
Followed by a reboot of the server.
If the above does not resolve the issue, then the following will usually resolve the issue.
- Add CWAService account to the Local Administrator Group on the CWA Server
- Add CWAService account to the AD Domain Windows Authorization Access Group
- Disable the following on the CWA Server NIC
- Jumbo Packet
- Large Send Offload
- TCP Checksum Offload
Microsoft KB 968978 References above steps.