I think know exactly the issue your having bc i'm having the same one right now. Trying to create / join a lobby through faf just ends up sitting forever with the "connecting" screen starting at you from within the client.
If its the same as me then, I have already tried running FAF "forged alliance.exe" directly through the c:\programdata\FAForever and loading an offline skirmish match and interestingly enough it too sits on the "connecting" screen even though i'm technically playing offline.
-I have also cleared cache, game files, settings
-I have also deleted & reinstalled the steamapps/common/supremecommander , FAForever, and Forged Alliance folders
-I have also deleted & reinstalled the c:\programdata\FAForever
-I have also reinstalled the FAF client
-I have also repair installed C++ redistributable(s) (bc why not)
My System Specs:
i7-5930k CPU
GTX 950 GPU - Drivers Up to Date
16 GB DDR4 RAM
Windows 10 64bit PRO v 1607 - and up to date
Honestly, i've been at this a little bit now and i'm honestly gonna just put on a fresh copy of windows 7 (instead of 10) on a new partition instead of trying to fix it.
**EDIT: Using downlords FAF client works without issue ... this really confuses me