Why won't my Galaxy S3 connect to strong wifi signals?

[Jonbelize]

Galaxy S3 Won't Connect To Strong Wifi Signals

Hi I have a galaxy S3 for less than a year now. Ever since last month I was able to connect to the router on weak signals or even strong signals. The only way I can connect to the wifi router is if I stand right next to it. If I go a couple feet away it will say its connected but I wont have any internet access. If i try to connect a few feet away from the router it will try to connect and will eventually say "Authentication Error".
This is really making mad because my phone is basically half useless without wifi on it. This happens on my router at Home, Work, and my brothers house. My mom has a HTC One X and the internet works like a charm at all these places. Please help I've been looking for a solution for a long time but all the forums and solutions I've found dont work

Thanks - Jon

 

[Jonbelize]

Re: Galaxy S3 Won't Connect To Strong Wifi Signals

I Flashed my S3 to stock ROM hopefully it would've fixed it but it apparently this did not fix the issue

 

[AxlMyk]

Re: Galaxy S3 Won't Connect To Strong Wifi Signals

Open the phone and remove the battery. With a small Philips screwdriver, very gently tighten all the screws you see. Replace the battery and back.

AC App on SGS3