iOS 9.2, wifi connected with full strength but does not work. LTE/4G working fine. Have tried resetting network settings and rebooting phone multiple times.

I've reset netwrok settings, reset the phone etc multiple times. Sometimes after a reset, the wifi will work for a couple seconds before stopping again. LTE has been working fine the whole time. My phone connects to the wifi at my workplace and works, and it connects to the wifi at my home but doesn't work. It also connects to unsecured xfinity wifi and works. I thought it was the problem with wifi only working on unsecured networks, but my workplace wifi is secured..

Last night I went to my parents, and was able to connect to their secured wifi and the internet worked. This morning, I'm having the same issue again with the wifi being connected fully but not working. Again, LTE/data works fine, and I've reset network settings and reset my phone with no luck.

Any help would be greatly appreciated.