Guys I was having this issue, and I found a fix that worked for me.
The Wifi on my last rom was working fine, as was on my current rom, until I switched on a setting, "Enable wireless display". It was the only common thread between the two, and as soon as I turned it on, I lost Wifi and got the "WPS failed" message when refreshing networks.
Once I turned off "Enable wireless display" (and rebooted with fixing persmissions, not sure if that's a necessary step), I had working Wifi again.
Settings > Display > Cast Screen > uncheck "Enable wireless display"
Hope this helps some of you.
Sprint Samsung Galaxy S3
Evo 4G, Hardware Version 0004
Rom: Team DIRT | PARANOIDANDROID
Kernel: Mason I