I’ve had a few clients and colleagues notice that they are no longer able to sign into Skype for Business after installing Windows updates sometime in December. The error message they receive when they attempt to sign in is as follows:
Can’t sign in to Skype for Business
The address you typed is not valid.
Valid addresses use the format username@domain (firstname.lastname@example.org). Make sure there are no spaces in the address.
Click Back to retype the address.
What I’ve noticed back in December was that the only way to fix this issue was to uninstall the updates outlined in the following KB article:
MS15-128: Description of the security update for Lync 2013 (Skype for Business): December 8, 2015
Now that we’re into the 2016 new year, it looks like Microsoft has released the following KB that outlines this issue:
"The address type is not valid" error when you sign in to Lync 2013 (Skype for Business) by using domain\username format
… and released a patch offerred in the following KB to fix the issue:
January 12, 2016, update for Lync 2013 (Skype for Business) (KB3114502)
The 64-bit patch found in the KB above is name lync2013-kb3114502-fullfile-x64-glb.exe and is 106,360KB in size. I’ve tested this with a few SfB clients that exhibited this issue and can confirm that it fixes the issue.