How To Fix Connection Problem or Invalid MMI Code Error

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 balance, or sometimes it’s just a prefix 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.

Simple Reboot

Simply turn off your phone and reboot again, see if that helps.  This may sound simple, but sometimes that’s all it takes!

Reboot in Safe Mode

By using your phone in safe mode, you can better troubleshoot your phone since it will run just the stock Android programs.  By eliminating all other apps running in the background, you can test to see if the problem persists without other apps running.

So to solve the Connection Problem or Invalid MMI Code issue, let’s reboot in safe mode.

To reboot in safe mode:

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

Once in safe mode, try entering the MMI code you were using before to see if the problem persists.  If you don’t have issue sending the message at this point, then most likely an app you recently installed is causing the conflict.  You can start by uninstalling the most recent app and go from there.

Add a plus sign (+) or comma (,) to the code

Try adding a comma to the end of your MMI code and dial again, for example, if you were trying to dial *1234 then try dialing *1234, you can get the comma by holding the asterisk (*) button for about 3-5 seconds.

Or try adding a plus (+) sign after the asterisk (*) sign in your MMI code.  For example, if you were dialing *1234 then try dialing *+1234 you can get the plus (+) plus sign by holding zero for about 3-5 seconds.  The plus sign should get rid of the error message and allow the call to go through.

Check Network

You could be getting the Connection Problem or Invalid MMI Code error because you are not getting reception.  Try setting your wireless provider, go to:

  1. Settings
  2. Network Connection
  3. Mobile Networks
  4. Network Operators
  5. Search Networks and select your wireless provider

You might want to try this method a few times before giving up on it.  It might take a few tries before it connects.  If the network search does not find your carrier, then you might want to check your SIM card.

Check Sim Card

If you have a dual sim phone, you have two choices here.

  1. Disable on of your SIM cards and activate only the SIM card that you plan on using to send the MMI code.  The phone may not be using the correct SIM card if you had both SIM cards running together.
  2. Under your phone’s dual SIM settings, find the voice call settings.  There it should give you an option to select with SIM card to use or “Always ask”, choose that “Always Ask” option.  When you try to dial the MMI code, the phone will prompt you and ask which SIM you want to use, that why you will have the option to select the correct SIM card.

If you have a traditional single SIM card, try something simple like pulling your SIM card and blowing on it, wiping it down a little, and plug it back in.  See if that will re-establish connection.

Turn on SMS over IMS

This step is for the tech geeks and we won’t get into details on how to do it since any wrong move using this method could destroy your phone, or just cause more headache to undo.  It basically involves you using the Android secret code *#*#INFO#*#* or aka *#*#4636#*#* to enter the Android Testing Menu, this is where professional technicians go to geek out on your phone.  You can run the ping test and activate radio and turn on SMS over IMS here that could solve your “Connection Problem or Invalid MMI Code” problem .  If you really want to try this method, feel free to google “how to turn on SMS over IMS“.

5 thoughts on “How To Fix Connection Problem or Invalid MMI Code Error”

  1. i have spent 2 days trying to fix the problem and your post immediately resolved the issue thanks a million

  2. I bought Huawei LUA-L01 from the other shop at small street jhb, the phone was just working perfect for 4 day. There after its start saying sim card error I took it back but this guy in the shop did nt help. He told me it was not him the one who sold the phone to me was not around . how do I fix this thing

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