Connection problem or invalid mmi code
If, when you try to make a call, send an SMS or make a request for account balance, a message about a connection problem and an invalid MMI is displayed on the phone screen, then you should do simple manipulations to restore the connection. There is nothing complicated about them and even an inexperienced user can perform them. First, a quick introduction to the MMI code
The MMI (Man-Machine Interface) code is used to generate a USSD request from the keyboard of a mobile device. It starts with an asterisk and ends with a hash. When performing more complex queries within code, an asterisk is used to separate parameters.
We usually use such combinations when requesting balance information, validity period, at replenishing your account etc.
Sometimes, when performing such a request, an error is displayed on the screen: “Connection problem or invalid MMI code.”
There are several ways to resolve this error.
SIM card problem
Like all electronic products, the SIM card is subject to physical wear and tear and may not function correctly. To correct the connection error, you must contact the service center to replace the card. However, the phone number will remain the same. It is recommended to replace the SIM card every 2 years.
Insufficient 3G coverage
Mobile operators are constantly improving their coverage capabilities and using third-generation 3G communications, but it does not always work as expected.
Modern telephones are also prone to modernization. For this reason, by default they use the ability to automatically connect to GSM/WCDMA. But with 3G connectivity interruptions, this network is not always stable.
To eliminate the error when there is insufficient coverage, you need to set GSM network in the following way:
- go to the phone settings;
- then go to the “Network” menu and select “Mobile networks”;
- in the “Network mode” setting, change the network mode to “GSM only”;
- reboot the phone.
This mode does not have to be changed permanently. After a while, try turning on the previous network mode again. New coatings allow you to use smartphones to the fullest: high-quality video communication, use of high-speed Internet, etc. But this does not always mean comfort if the coverage is insufficient or is constantly being improved.
