Many Android users see the error message "Connection problem or invalid MMI code" when trying to dial USSD codes like *99# or *123#. This problem happens mostly on 4G networks, but the same codes work fine on 3G and 2G.
If you are facing this issue, don’t worry! This guide will help you understand why this happens and how to fix it step by step.
Why Does This Error Occur?
This error happens mainly because of two settings on your phone: VoLTE (Voice over LTE) and VoWiFi (Wi-Fi Calling). These settings force your phone to use a 4G network for calls and USSD codes. But in some areas, your mobile network provider does not support USSD codes on 4G. As a result, your USSD code request fails, and you see this error.
In simple words, your phone is trying to send the USSD request through 4G, but your network provider only allows USSD codes on 3G or 2G. This is why you get the "Invalid MMI Code" error.
There are also other reasons why this error may occur:
- VoWiFi (Wi-Fi Calling) is enabled, which can interfere with USSD requests.
- Your mobile network does not support USSD codes on 4G.
- Incorrect network settings on your phone.
- Your SIM card is not inserted properly or has network issues.
- A software bug in your phone is causing the issue.
How to Fix the Issue?
The best way to fix this problem is to turn off VoLTE and VoWiFi or switch your network to 3G or 2G while using USSD codes. Below, we will guide you through the steps to do this.
Step-by-Step Guide to Fix the Connection Problem or Invalid MMI Code Error
If you are facing the "Connection Problem" or "Invalid MMI Code" error on your Android phone, don’t worry! This guide will help you step by step to fix the issue easily.
1. Turn Off VoWiFi (Wi-Fi Calling)
VoWiFi allows you to make calls using a Wi-Fi network instead of your mobile network. However, sometimes, this feature can cause issues with MMI codes. You need to turn it off using the methods below.
Method 1.1: From the Notification Bar
- Swipe down from the top of your screen to open the Notification Panel.
- Look for the VoWiFi or Wi-Fi Calling icon.
- Tap on the icon to turn it off.
👉 If you see the VoWiFi OFF icon, it means the feature is successfully disabled.
Method 1.2: From Phone Settings
- Open Settings on your Android device.
- Go to Connections or Network & Internet (this option may vary).
- Tap on Wi-Fi Calling or VoWiFi.
- Toggle the switch OFF for both SIM 1 and SIM 2.
Note: If you use two SIM cards, make sure to disable VoWiFi for both.
2. Turn Off VoLTE (Voice over LTE)
VoLTE is another feature that can sometimes cause errors with USSD codes (MMI codes). Disabling it might help fix the problem.
Method 2.1: From the Notification Bar
- Swipe down from the top of your screen to open the Notification Panel.
- Look for the VoLTE or 4G Calling icon.
- Tap on the icon to turn it off.
👉 If you see the VoLTE OFF icon, it means the feature is successfully disabled.
Method 2.2: From Phone Settings
- Open Settings on your Android device.
- Tap on Connections or Mobile Network.
- Select your SIM card.
- Find VoLTE Calls and toggle it OFF.
Tip: If you have two SIM cards, disable VoLTE for both.
Conclusion
If you are facing an invalid MMI code or connection problem error, the first step is to disable VoWiFi and VoLTE using the methods above. These settings sometimes interfere with USSD codes, causing errors.
If the issue is still not resolved, try restarting your phone and dialing the code again.
💡 Still facing the issue? Let us know in the comments, and we will help you further!
✅ Did this guide help you? Share it with others who might need it!
No comments
Post a Comment