When you dial any wrong number on your device, you can show the error connection problem or Invalid MMI code android phone or tablet. This MMI code generated when dial number and USSD code running. You can see this connection problem or Invalid MMI code error when dial wrong number (*84536#), checking account balance or other payment via code, low signal network, SIM problem and other reasons.
This invalid MMI code error on android phone is found on mostly dual SIM when USSD code running, sometimes one SIM card phone generated this error. Below you can see troubleshooting steps to fix connection problem or Invalid MMI code android phone.
How to fix connection problem or Invalid MMI code android phone or tablet
1st Method: Restart your android phone
Restart android phone to fix error, it may be works. If not work then turn on airplane mode, after few minute turn off it and restart device.
2nd Method: Check Cellular Network settings
Different device is different settings to check network settings. Below you can see Moto G4 plus (Android 7.0 Nougat) settings.
Step 1: Go to “Settings”
Step 2: Under wireless & networks, tap on “More”
Step 3: Touch “Cellular network”
Select your network to check it. You can change preferred network type (4G/3G/2G), set access point and enable data roaming using this cellular network settings.
3rd Method: Boot android phone into safe mode
Step 1: Press & hold the power button in your phone
View the “Power Off” screen.
Step 2: Touch & hold the power off
This message appear on screen: Reboot to safe mode
Step 3: Tap “OK”
Now enable safe mode on your android phone or tablet. You can see the “Safe mode” at bottom left side screen on phone.
Now check your device work perfectly in safe mode. If works without any problem, downloaded apps may causing problem in android device. One by one uninstall downloaded apps from device. Check after every app uninstall to phone working fine. To exit safe mode, press power button 30 seconds.
If you will find which app can cause the connection problem or Invalid MMI code error android device, delete it.
Check this: Fix Error retrieving information from server
4th Methods: Fix connection problem or Invalid MMI code android to add coma / Plus symbol
It is very simple trick to solve Invalid MMI code error on your android device.
If your prefix code is *84536# just add the comma (,) symbol in the ending code (*84536#,).
If your prefix code is *84536# just add plus (+) symbol after star (*+84536#).
Now check the fix error on your device.
End the list of possible solutions to fix Fix connection problem or Invalid MMI code android phone. If you have known other method to fix this error, please share with us. If you find above steps helpful, share it with your friends.