saxby:
you have to change your network provider o

How can one change network provider?

Happened to me too

The same

The easiest thing you can do when Mobile Network State Disconnected is to check if the SIM card is working. To do this, remove it from the smartphone and check if it will work on another phone. If it won't work there either, then this is the problem. In this case, you need to contact your service provider in the customer support centre. If you cannot solve the problem with your mobile operator, you will have to go to a service centre. They will already solve your problem.