HTC Wildfire S saying Invalid MMI code when making a call

[#4]

Few weeks ago I have purchased the HTC Wildfire S. From yesterday I cannot make any calls from my phone. Whenever I try to make a call for some reason phone simply rejects it and furthermore it says Connection problem or invalid MMI code. How can I fix it? I cannot call customer service. Any other solution?

[Memphis M]

I did not even know I had my cell phone flashed. I tried wipe out the Data Cache manually but has brought nothing. I don’t know whether factory settings will solve the problem. i will do that once. If it didn’t solve the problem then I will surely go for either firmware flash or update. Other than this I didn’t see any kind of solution on this forum page or on any other.

[akkiiii]

It seems to me that the problem is the network connection, whether 2G or 3G. Look inside your network configuration, if you got it the NPC, then you cannot call. The same thing happened to me several times. In general it solved, leaving only the APN and deleting all others. I hope that it will solve your problem.

[JyotiT]

I have been almost on the same problem: Wanted to send a text message, and then continuously getting “connection problem or invalid mmi code.” I urge you to check the number of the message center. There are occasional problems, because the "+##" might be missing before. To know about the message center number, you should call the network operator customer service center. They will tell what the number is.