Before my previous post, I’d make some changes to the Web Services FQDN, from the default of Override Pool:

To an actual Web Service FQDN – abs.contoso.com

After publishing the changes, I wasn’t able to login to either the Control Panel or even via the IE browser with the error of 401.1 – Unauthorized:

So now, nothing to panic about, if you happen to go through the Topology Builder once more, you may notice that you’ll need to rerun the Lync Setup to get the configurations re-populated:

Just pop-in the Lync Server 2010 DVD installer, run the setup and select this option once more:

After the setup has completed, you should be able to login to the Admin Console once more.