Hello, I'm using a galaxy s3 phone with the linphone client (wifi only) in our plant. It can work flawlessly for many days and all of a sudden, it won't register anymore. I use the TCP transport. When this happens, I change it to UDP transport and it works again. If I want to use the TCP transport again, I need to restart the 3cx server and then the phone will register properly with the TCP transport. I have tried a few voip clients and they seem to behave the same way. I'm testing on another phone also. The reason we can't use the 3cxphone is because we can't change the ringtone and the phone doesn't vibrate when we receive a call. Since there's a lot of noise in the plant, we need a client that vibrates when receiving a call. Any clues ? Thanks.