Yesterday I bought my new Sony Xperia C4. When I tried to connect to the wi-fi network at home, I got authentication problems. I managed to solve this by pushing the WPS button. But there's another problem. Because the wi-fi signal is pretty weak upstairs, we have a devolo 500 wi-fi booster, which always worked fine. I just can't get my new phone connected to it. It saves the connection but keeps on giving an authentication error and I don't know how I can solve this. I did NOT make any password mistakes, I can tell that for sure after enough tries. I even tried standing next to the booster and that doesn't work either.