I have only had the phone for a week or so and never been able to use the wifi. Whenever I connect to it the words come up to say "connecting" then I put in my password and then click ok. The password is remembered but then it just disconnects from the router.
My router is a Belkin b96 duel band. I have read and tried as much as I can on these forums and nothing worked.
So what I have done is go into my router setting and opened a cafe style guest account with its own password. This still allows my own computer to run and also I can allow guests in the house to let them use their phones, ipads and other things without having to give them my correct password. I can also control what sites they can go to so no nasties there.
I hope this might help anyone out there who is still having a problem connecting onto the net with wifi on their own galaxy ace.