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

Sometimes a message pops up saying “Connection problem or invalid MMI code” and it can be frustrating for Android users. When the message with the invalid MMI code appears, it generally means that you will not be able to call or text until the problem is resolved. This can occur for many reasons.

Fortunately, there are several ways to potentially fix the Android “Connection problem or invalid MMI code” error. Try the following options below. If a process doesn’t resolve the issue, move on to the next.

What is an MMI code?

Every SIM compatible device has a plethora of codes and numbers, it can be difficult to identify the purpose of each. An MMI (Man-Machine Interface Code) code starts with an asterisk

or pound sign (#) that allows users to enable or disable various star code functions (*#06# to reveal IMEI, for example).There are several reasons why the “Connection problem or invalid MMI code

” error message appears on your phone. The main reason is a problem with the carrier or problems with the SIM authentication on the smartphone. The error is quite common on phones with dual SIM capabilities, but it occurs on others as well.

Ways to Fix the MMI Code Error

There are several methods to solve the “Connection problem or invalid MMI code” on Android device. We cover them from the simplest to the more complicated.

1. Restart the Android device

  1. The first way to try to fix an invalid MMI code is to restart the smartphone. Keep the Power button and the Home button
  2. simultaneously until the phone turns off and starts to vibrate; wait for it to reboot. You can also use the . keep pressed Power button until the Shut down options menu appears, then selectRestarting


2. Run your device in safe mode

  1. It is possible that third party software is interfering with your connection and causing an MMI error. Fortunately, it’s easy to rule this out. Here’s what to do: Restart your phone in safe mode. You can do this by pressing and holding the power button (button combination) on your Android device. Then long press thePower icon
  2. . Tap Safe mode
  3. from the menu that appears.

Now use your phone in safe mode for a while to see if the MMI error shows up.

If your phone is not showing any error codes, then third-party software is interfering with your network. You should start by uninstalling third-party apps. Start with the applications you installed around the time you started seeing the error. When you follow Settings>Apps

scroll down path and uninstall any apps you think are the culprit. Then turn your phone out of safe mode and see if the error shows up. Keep doing this until the MMI code stops.

3. Use Airplane Mode

  1. Some users have had success using Airplane Mode to fix their MMI code error issues. Go to Settings and turn Flight mode untilon
  2. . Wait about 10-30 seconds and then turn Flight mode untilOut


Since an MMI code error can occur due to weak signal strength, this may reset your connection and correct the error.

4. Reset your network settings

  1. Since we know that the MMI error indicates a problem with your device’s cellular connectivity, the next logical step is to reset your network settings. Perhaps your network settings have not been updated properly or there is a malfunction in the system. Doing a network reset will clear any trouble codes and you can start over. Here’s what to do: Open the Settings on your Android device. Then tapGeneral management
    . You can also use the search icon and type ‘Reset’
  2. to skip step 2. Scroll down and tapReset
  3. . Tap ResetNetwork Settings
  4. . Tap Reset settings

to confirm. Your phone will reboot.

When your phone backs up, the error should disappear.

5. Change the prefix code

Another way to solve the connection problem or invalid MMI code on an Android smartphone is to add a comma to the end of the prefix code. When a comma is added, the operation is forced to run and ignore errors.

  1. Below are two different ways to change the prefix code.If the prefix code (*2904*7#), then add a comma to the end, similar to this (*2904*7#,
  2. ). You can use the + symbol after *similar to this (*+2904*7#


  1. 6. Activate radio and enable IMS via SMS Go to thekeypad
  2. .Type in (*#*#4636#*#*
  3. ) NOTE: You don’t need to press the send button, it will appear automatically in the service mode.
  4. Enter service mode.
  5. Select Device Information or Phone Information.
  6. Select Run Ping Test.
  7. Click the Disable Radio button and the Galaxy will reboot. SelectRestart


Frequently Asked Questions

Hopefully your MMI error has disappeared at this point. But if you still have questions, read on.

Do I need to get a new SIM card?

If you’ve tried all the solutions above and the error still persists, you may need to contact your mobile operator for more information. They can recommend a new SIM card or they can resend OTA (over-the-air activation).

Android MMI code error fixed

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

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