I was trying to start mobile cellular data. It's been a year I can't turn it on. Usually, I am currently using Postpaid sim card. When I was using Prepaid sim card than, I could turn mobile cellular data. I was reading the [article](https://cellularnews.com/cellular-network/10-easy-fixes-for-mobile-data-not-working-on-android/). They said to change APN protocol. I have reset APN. But, I can't find anyway to configure existing APN protocol for Airtel sim card. But, I can't create a new one. They had said to `Opt For a Factory Reset`. I had reset my mobile 5-6 months ago. In the [article](https://www.maketecheasier.com/fix-cellular-data-not-working-on-android/), they had said to Reset Your Phone’s Network Connection by the "code" `##72786#` then, I am getting `connection problem or invalid MMI code.` My sim card is 3G. I don't think that "I didn't make it 4G that's why I am getting the problem" (cause, my prepaid sim card was 3G either). I don't have any data limit also. I have rebooted my mobile thousand times. My mobile isn't in safe mode also. Sim card isn't expired also.
