Have you ever seen the error message as “Connection problem or invalid MMI Code” on your android device? For this question, most of the Android smartphone users give an answer as Yes. Because all the Android users have faced this error message at least once on their device. This error message often comes when you are checking your account balance. It also comes when you are topping up the balance of your SIM account. This message occurs because of the SIM authentication problem on your Android device.

If you get the Connection problem or invalid MMI Code message, it’s a serious issue happens with the phone. First of all, MMI code means Man-Machine-Interface. Sometimes, you may also get this message while making calls to someone. It will put the restriction while sending and receiving the calls as well as text messages. This error message is mostly seen on the dual SIM Android mobile phone. Sometimes, the users of single SIM Android phone may also get this error message.

But, is there any solution to get rid of from this error message? Yes, why not! We have a solution to get rid of this issue.

How To Fix Connection Problem or Invalid MMI Code

How to Fix connection problem or invalid MMI code?

Here, we will also discuss some fix to solve this error message on an android smartphone. Now, visit the below fix and keep solving the error message.

  1. By Restarting the device
  2. By Deleting the App which causes this MMI Code Error
  3. By Modifying the Prefix Code
  4. By Entering the Android Phone into Device Information Mode
  5. By Navigating the Network Connection Through the Settings

1.) Restarting the Android Mobile

The restarting of the device is the simplest way to get rid of from the issue of the error message. This trick will work several times. But, sometimes due to some reasons it may not work well. To restarting your Android device, just follow the below steps.

  • Press and hold the Power button of your Android mobile.
  • It shows you a pop-up with some options. The options like Switch Off, Restart, and Airplane Mode.

MMI Code 1

  • Among this options, to restart the device, tap on the option of Restart. The restarting of the device takes awhile.

Wait until the device is turn on again. After the device is starting on, then try to call someone. If still, the error message comes, then go ahead with the second fix.

2.) Deleting the App which causes this MMI Code Error

This fix is also one of the most effective fix ever, which is about the disabling of App. By deleting the app, which causes the MMI code error, you can resolve this error message issue. But, the hardest thing is that how to find that error causing app. To find that app, you need to boot your Android into the Safe mode. After entering the device into the Safe mode, it does not allow any apps to load on the device. It disables all the pre-installed apps which come with the smartphone.

To enter your device into Safe mode, follow the below steps.

  • First of all, turn off your mobile.
  • Then, press and hold the Power key.
  • It will prompt you with the option of Power off, Restart and Airplane mode. Now, tap and hold the option of Power off, which comes by pressing the power button.
  • It will again prompt you with a pop-up of Reboot to safe mode. To entering into safe mode, press on OK.

MMI Code 2

  • After tapping on OK, the device takes awhile to turn on into Safe mode. If you have done above steps properly, then you can see safe mode text at the left bottom corner.
  • Now, open the dialer and enter the prefix code. For example, *125#.
  • If it works, then there is any app which causes the MMI Code error.
  • Now, reboot your Android device and delete all the downloaded apps that you have installed recently.

If above trick does not work for you, then the next is also an option to perform.

3.) Modifying the Prefix Code

After performing the above fix, if still, the error message appears, then try this easy fix. In this fix, you just have to add a comma at the end of the prefix code. By using the sign of plus “+” after the ‘*‘ in the prefix code, you can also solve this MMI Code error.

  1. If your Prefix code is *2409*8#, then add the comma at the end of the code. And use the code as *2409*8#
  2. Use the + sign after *. Use the code as *+2409*8#.

After trying this fix, if still, you see the error message, then move on with the next one.

4.) By Entering the Android into Device Information Mode

To solve the MMI error through this fix, then you have to enter your device into Device information mode. After entering the phone into Device information mode, just follow the below steps.

  • To enter into Device information mode, dial *#*#4636#*#* in the dialer of the phone.
  • Go to the Device Information or Phone Information option.
  • Here, tap on the “Run Ping Test”. It takes a little bit.


  • After that, click on the option of “Turn Off Radio” and “Turn on SMS over IMS” one by one.

Then, reboot your android device and check that if the error message is coming or not. If still comes, then try one of the best fix listed below.

5.) By Navigating the Network Connection Through the Settings

Here, we will mention the steps for according to the Android OS 6.0 Marshmallow. So, other users, the options may be different, but the process is same.

  • First of all, go to the Settings of the device by launching the Menu.
  • Here, go to the More option under the tag of Wireless and Networks.

MMI Code 3 1

  •  Now, go to the option of Network operators by going into the Cellular Networks.
  • It will start to search out the available networks. It will take your little bit.

MMI Code 3 2

  • Now, select any one depending on the SIM card. And even after then, you have noticed the MMI error, then perform this same process for 5 to 6 times.

This will solve the error message of Connection problem or invalid MMI Code. Now, we have discussed detailed steps to fix MMI Code error message.

We hope that this guide has helped you to get rid of connection problem or invalid MMI code error. Also, share this useful tricks to help other peoples having a similar issue.