If you are android phone users you must be familiar with ‘connection problem or invalid MMI code’ problem. This problem is nerve-wracking one, particularly when you try to call somebody in difficult situations. We all have got through this problem while inquiring about balance, recharging mobile and calling somebody. The problem is very common but, do you know how to get over it. If not we are guiding you how to overcome this difficulty. Here are four methods.
Enable safe mode
Safe mode helps to disable all the pre-installed apps on your phone for the time being. And it detects the app which is creating such error. To enable the safe mode, turn off your phone and hold the power button. Keep holding the power button, until you see the notification box asking you to enter safe mode.
2. Make changes to prefix code
The another way to solve invalid code error problem is to make changes on prefix code. Add comma or plus(+) at the end of the prefix code (*125#). It will solve the connection problem.
3.Restart your phone
Make several attempts of turning off your phone and turning it back on. This will also help you to solve the problem.
4.Select mobile networks manually
Your mobile network gives you to choose between manual network or automatic network in network settings. From these options select the networks manually, repeat the process several times until you overcome the connection problem.