How To Fix Connection Problem or Invalid MMI Code Error In Android [Updated 2024]

Every now and then, you may run into the Connection Problem or Invalid MMI Code pop up error on your Android device. This generally happens when a user is trying to send an Man-Machine-Interface code, aka MMI code.
What is a MMI code you ask? It’s those funny codes you enter on your dialer that includes an asterisk (*) or hash (#) characters, like calling #BAL on your Verizon Wireless phone to check account balance, or sometimes it’s just a prefix code you enter before a phone number.
If the Connection Problem or Invalid MMI Code problem is driving you nuts, we got a few solutions that should solve your issue.