In most cases, after turning on the SIM card Internet, the Internet connection will not be established. This problem usually occurs after exiting the flight mode or after restarting the phone. There have also been updates. Of course, this is not a permanent problem and sometimes it does occur.
This problem is usually caused by the automatic deletion of all APNs, which can only be solved by restoring the settings and restarting.
And sometimes it is not a problem of APNs and we must change the settings of the CDMA option to solve the problem of SIM card internet connection. This issue has caused many problems in Internet connection.
Test method: The problem of internet connection sometimes exist