This problem often occurs when you turn your smartphone off and on again, insert a new SIM card, or, in some cases, while using your phone, when your SIM card is suddenly undetected.

If your phone suddenly won't recognize your SIM card, don't panic. There are a few things you can do to try and resolve the problem. Here's what to do.

You can't make calls if you get the "SIM not provisioned MM#2" error, but it's easy to fix.

“No SIM Card” error is one of the common issues on Android devices. In this troubleshooting article, we’ll guide you on how to address the problem on Galaxy S10.

In conclusion, the No Sim Card issue is a common problem for both Android and iOS, but it’s certainly fixable. While there are a lot of causes for this issue, the good news is that there are ...

Fix #5: Clear the cache and data of the Phone app. If reinserting the SIM card did not fix unable-to-answer-calls problem, your next move is to clear the cache and data of the dialer app or Phone app.

When that happens, you might see the "your phone is not registered on a network" on your screen, which means your SIM card can't connect to your wireless provider's network.

If you have switched SIM cards in recent days, it is possible one of them has been lost or damaged while being removed from the slot in your phone's battery door. How to fix the problem?

If your Android phone keeps dropping calls, there are multiple possible causes and solutions, though the problem is usually very easy to fix.