How to Fix Connection Problem or Invalid MMI Code on Android Device

For Android users, sometimes a message saying " Connection problem or invalid MMI codepops up and can be a frustrating thing to deal with. When the invalid MMI code message appears, it usually means that calls or text messages cannot be sent until this issue is resolved.

But there are several ways to fix Android login problem or invalid mmi code which will be explained below.

What Causes the MMI Error

There are several reasons why theConnection problem or invalid MMI code » An error message is displayed, the main reason can be due to a problem with the operator or SIM authentication problems on the smartphone.

Ways to Fix MMI Error

Here are several different methods to fix login problem or invalid mmi code on Android device.

Restart the Android device

The first way to try to repair an invalid MMI code would be to restart the smartphone.

  1. Hold it power button and home button at the same time until the phone turns off and starts vibrating, wait for it to restart.
  2. You can also press and hold the power button until the Shutdown Options menu appears, then select Restart.

Change prefix code

Another way to fix connection problem or invalid MMI code on Android smartphone would be to add a comma at the end of the prefix code. When a comma is added, it forces the execution of the operation and ignores any errors.

Below are two different ways to do this:

  1. If the prefix code is (* 2904 * 7 #), then add a comma at the end, similar to this (* 2904 * 7 #,).
  2. You can use the + symbol after * similar to this (*+2904*7#).

Activate the radio and activate IMS by SMS

  1. Access the numeric keypad.
  2. Type (* # * # * # * # 4636) NOTE: No need to press send button, Service mode will appear automatically.
  3. Enter mode of service.
  4. Select Device Info ou Phone Info.
  5. Select Run the Ping Test.
  6. Click on the Turn off the radio then the Galaxy will reboot.
  7. Select redémarrer.

Check network settings

The steps to access your network settings will be different, but the concept is the same. follow to check your network settings.

  1. Go to Parameters.
  2. Now select Network connection.
  3. Tracked by mobile networks.
  4. Then, Network operators and select the wireless service provider while searching.
  5. You may need to reconnect for 3-4 more attempts before it starts working again.


In conclusion, there are a few methods/options you can use to fix the MMI error on your phone, some a bit more complicated than others. While most MMI errors occur on dual SIM phones, it also occurs on single SIM phones due to weak signals or tower network issues. If the solutions above do not work for you, contact your service provider for assistance.

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