Fix ‘Connection Problem or Invalid MMI Code’ issue

Fix Connection Problem or Invalid MMI Code issue: MMI codes are not used often by phone users, but when they are, it is very important that they work correctly. So, it can be very frustrating for an Android user to see a message that says “Connection problem or invalid MMI code.”

Because of this error, they can’t make some calls or send some text messages until they fix it. In this guide, we’ll show you how to fix an Android device’s connection problem or invalid MMI code. There are, luckily, several ways to fix this problem, and if you’re having it on an Android device, you should try each one in turn.

Fix ‘Connection Problem or Invalid MMI Code’ issue

Reset Network Settings

  1. Go to Settings
  2. Tap General Management
  3. Select Reset  
  4. Tap Reset network settings.

Turn Off One SIM Card

  1. Go to ‘SIM Card Manager’ on your device.
  2. Turn off the unused card.
  3. Test to see if it works.

Clear Mobile Data and Cache

  1. Go to ‘Settings’.
  2. Choose ‘Applications’.
  3. Select ‘Contacts’ and press ‘Mobile Data’.
  4. Choose the options to clear the data.

Select a Network Operator

  • Open the Settings app.
  • Go to Connections or Wireless & Networks.
  • Select Mobile Network.
  • Click on Preferred Network Type. You can choose 3G, 4G, or 5G. It depends on you.
  • Now, select Network Operators. A list of operators will appear after a short search.
  • Choose the operator of your choice.
  • Close the Settings app and restart your phone.
  • Dial the MMI code.

Reboot in Safe Mode

  1. Turn off your phone.
  2. Press and hold the power button to turn on, continue hold the power button until the logo display appear.
  3. Press and hold the volume down button until the reboot is finished.
  4. You should see “Safe mode” at the bottom left corner of your display.

Turn on SMS over IMS

  1. Use the Android secret code ##INFO## or dial 4636 in the dialer (aka ##4636##).
  2. This will enter the Android Test Menu or information mode.
  3. In the Test Menu, professional technicians can access and explore your mobile or device information.
  4. You need to play ping test and activate radio in this menu.
  5. Additionally, turn on SMS over IMS to potentially solve the “Connection Problem or Invalid MMI Code” problem.
  6. If you want to learn more about enabling SMS over IMS, you can Google “how to turn on SMS over IMS.”

Turn Airplane Mode On and Then Off

  • Scroll down from the top of your screen to see the options.
  • Click on the Airplane Mode button in the options to turn on Airplane mode.
  • Wait for about 20 seconds.
  • Click on the Airplane Mode button to turn it off.

What is an MMI Code?

Any device that works with SIM cards has so many codes and numbers that it can be hard to figure out what each one does. A Man-Machine Interface (MMI) code starts with an asterisk (*) or pound sign (#), which lets users turn on or off different star code functions (for example, *#06# to show the IMEI).

The “Connection problem or invalid MMI code” error message on your phone could be caused by a number of things. The main reason is a problem with the phone carrier or with how the SIM card works on the phone. The error happens a lot on phones that can use two SIM cards, but it can also happen on other phones.


What is the MMI code on a phone?

(Man Machine Interface code) A cellphone code that begins with a star/hash (*#) prefix. MMI codes are entered like telephone numbers to obtain a variety of information as well to enable and disable various actions. For example, entering *#06# on a GSM phone displays the model and serial number (see IMEI).

What does call forwarding connection problem or invalid MMI code mean?

An invalid MMI code is a mobile network error that has a range of problems, from connection issues to authorization issues. It mainly is a problem with a Sim Card and is an error that happens commonly with Dual Sim Card smartphones.Mar 23, 2023

Editorial Staff
Editorial Staff
The Bollyinside editorial staff is made up of tech experts with more than 10 years of experience Led by Sumit Chauhan. We started in 2014 and now Bollyinside is a leading tech resource, offering everything from product reviews and tech guides to marketing tips. Think of us as your go-to tech encyclopedia!


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