Connection problem or Invalid MMI code

[xJoshx]

Ok so I've had a problem for awhile now about this error message and I've put my sim card into another phone and it doesn't show up on there,but when I put my sim card back into this phone (A22 5G) it just gives me that error code!

What is wrong-?

[kavango]

My Samsung galaxy A10s connection problem /invalid code

[bitycoon]

My Samsung galaxy S20 has  connection problem /invalid mmi code. Please help.

I have reboot, enter safe mode, change sim and still get the same problem. 

[Hidey]

I can't access my balance from my Galaxy A12. It's saying MMI code invalid