If you get the following error when logging into vCenter(5.1U5): “A general system error occurred: Authorize Exception”
Restarting the Single Sign On service on your vCenter should resolve the issue. In my case the cause of this was due to the LDAP connection pool being exhausted. To confirm this check the ssoAdminServer.log found here:
Do a search for the following error: No ManagedConnections available within configured blocking timeout
If you find that around the time when you was logging in then your LDAP connection pool was exhausted. This issue is resolved in vSphere 5.5.
The VMware KB article for this issue 2055448: