Here at Technobezz, we covered a lot of Solutions for problems on almost all Mobile Phones. The Samsung galaxy variants are extremely popular and, we have written some of the simplest and helpful solutions for various issues. While there are plenty common errors on the Samsung galaxy, one of the problems that really caught our attention and, which was found to be the most difficult was the Connection Problem or Invalid MMI Code .

Here is what the user said: 

Hello, I am having connection problem or invalid MMI Code… I am unable to send or receive calls and text messages, and i cannot recharge airtime.

You usually see this error when you are about to check your account balance, Topping up, Recharging or performing any function designed by your Sim service provider, like adding a voucher to run a USSD code.

What causes Connection Problem or Invalid MMI Code

While different country cell phone providers vary, Invalid MMI Code error is found on mostly dual Sim smartphones, such as the Samsung galaxy S Duos.

How To Fix Connection Problem or Invalid MMI Code

Method 1

I am listing this solution first because users had less attention to this, yet it is the simplest and most effective one. App Disabling – there are a lot of users who have found a solution by deleting an app which may have been causing the MMI code error. However, this may not be the case for most people. To find out if there is any app that may have been causing you to get this error, you simply need to go into safe mode on your phone.In this guide, we will be using Samsung Galaxy.

What is Safe Mode?

Safe mode is very similar to a computer’s safe mode. It does not load any Apps. Basically, it temporarily disables all pre -installed applications and services that came with the phone.

 How to Enter Safe Mode

To enter safe mode and to find out if there’s a culprit app that may be interfering with the network operation of your phone, kindly follow the instruction below. App Like FX Camera is seen to be a treat in most cases. However, to enter safe mode:

• Turn off your phone
• Hold the Power button
• While holding the power button keep tapping on the menu button; this is the button left of the home key.
• You will be greeted with a safe mode logo at the bottom left of the screen.

Now it’s time to test .

• Enter the same Prefix code you were trying before within the dialer and see if it works eg “*135#
• If it works, then there is an app which is causing the Invalid MMI Code error on your android phone.
• Reboot your phone and remove any recently installed apps

Method 2

Another simple and effective way to fix Connection Problem or Invalid MMI Code on android phone is to add a comma at the end of the Prefix code.

For example:

If your Prefix code is *2904*7#, then adding the comma at the end would do just the trick which will look like *2904*7#,

OR

You can use the + symbol after * like *+2904*7#

By adding the comma it forces the operation to execute and overlook any error that’s in the way.

Method 3

Please also read :Secret Codes For All Samsung Galaxy Variants (S2/S3/S4/S5)

To Fix Connection Problem or Invalid MMI Code on Samsung galaxy , this method requires you to simply enter into device information mode and activating Radio to Turn on IMS over SMS

To Enter information mode :

• Dial *#*#4636#*#* in the dialer
• Navigate to Device/Phone Information
• Click on “Run Ping Test “
• After the Ping test is performed
• Click on “Turn Off Radio“
• Next, Click on “Turn on SMS over IMS“

IMS :IP Multimedia Subsystem
IP :Internet Protocol
SIP:Session Initiation Protocol

While this setting is off, SMS is sent or received over a period of 1x(times), the circuit switched connection

Finally reboot .

Method 4

Restarting your phone several times can do the trick. Basically, turn your phone on, navigate to network settings. Then hold the power and the home button together until your phone turns off. Then Turn it back on.

Method 5

On Technobezz, there are always more than one ways to solve a problem, and here we have a collection of solutions, These links below are articles for different problems. Even so, most of my users had found a solution by applying the same principle.

Navigate to these articles and follow the steps precisely :

Method 5A : Fix Invalid MMI Code: Insert SIM card to access network services

Method 5B : Fix Invalid MMI Code or Connection Problem on Samsung Galaxy S4

Method BC : Fix Invalid MMI Code By Restoring your IMEI Number

Method 6

Navigate to:

• Settings
• Network Connection
• Mobile Networks
• Network Operators, it will begin searching. You will see available networks present . Select your service provider (at&t or Verizon etc)
• If you selected one and you still encountering invalid MMI Code then,
• Connect again, normally it can take up to 4-5 attempts before it actually starts working.