I got the same problem with my note 3 (n9005) on every rom since 5.0.
I can see the AC WiFis, but I'm unable to connect. It makes no difference, choosing another channel or trying it in another network.
The behaviour: it tries to connect, (connecting..) after not even a half second, it just falls back into the state like I newer tried to connect (password is saved, and it don't says, it's a wrong password entered.) If I enter a wrong password, it tells me to reenter the correct password.
Any suggestions, what it could be?..
Thanks in advance