A generally fix to wifi connectivity issues, is a strict power cycle. First, touch and hold your connection on your phone, and tap: "forget network". Next, turn off the wifi setting on your phone, and then power down your phone completely. Next, unplug your router from the power source, and wait for it to completely shut down. Afterwards, plug your router back in and wait for the Internet and power lights to be on and solid. Then go back and power on your phone, turn on your wifi, and connect again. (*It would also be a good idea to rename the phone too, in this case, but before trying to connect again).