Having this issue at a few different sites with vCenter virtual appliance.
The issue is that you are unable to log in with vSphere or the Web admin interface. The error is: Wrong username or password.
You can, however login at the console with the same root username and correct password. The only fix so far has been a reboot of the vCenter virtual appliance. After the reboot, everything works fine again.
Not using any AD integration. Using internal Database and internal user names only.
