We have one user, out of about 100( that actually use Lync) who takes his laptop out of the office and can connect to Lync. Walks in the office and cannot connect to Lync. In the office Lync starts up and hangs on starting. Does not go anywhere, you have to end the process tree in task manager to close it. I have deleted his sip in app data, that fixed it temporarily. Thirty minutes later quit working. We also have uninstalled Skype and reinstalled it, along with doing an online repair.
To me it sounds like a network problem, however other people in the same office use it regularly, without issue.
Lenovo t450 Windows 7 (64) Skype for Business (32)
I am at a loss right now and have almost gave up trying to fix it. Any help is greatly appreciated.