I had a similar problem with my home wifi, here is how I finally fixed it. First find out what your routers ip address is, I looked on my wife's phone to see what ip her phone was connected to. Next press and hold the wifi you are trying to connect to, a window will appear with selections "Forget network" and "Modify network". Select Modify network, and check the Advanced options box. Scroll down to IP settings and press the down arrow. Then select Static and scroll down to the IP address line and enter the ip you wish to connect to and save. You may need to know the routers password to complete the save. Now go back out and check your connection. If connected, repeat the above process and change the IP settings back to DHCP. If you don't do this step your phone wont auto connect to other wifi networks. This worked for me, hope it works for you.