Connection Problem or Invalid mmi code

[kenneth2222]

No problem with signal and wifi. I cant make and recieve calls, even text message not allowed, and when I dialled *121# connection Problem or Invalid mmi code comes out. Please help me what to do. I have reset my phone to factory settings but nothing happened

[JiYong]

Can you tell us which provider you are on and in which country?

The MMI code *121# what is it supposed to do?

Can you disable Wifi and post a screenshot of your home screen?

I'm mostly interested in the top bar, so you can cut off the rest when your home screen reveals privacy information.

[Alexander1]

Mmi code is an error message from the network. I suggest that you raise this with your network provider to see if they can see what's wrong. You could also try with another SIM card in your phone. 

[kenneth2222]

I tried another sim card and it worked, im from Philippines btw. My problem now is the phone is openline to any network why it only worked in one network provider only. and I need to use my previous sim card. Here in Philippines our network provider names are Sun, Smart and Globe. The only network provider working in my phone is Sun, I need to use my Smart sim card. My Smart and Globe sim cards are now useless because It cannot make or recieved calls and text plus the connection problem and invalid mmi code problem too.

[JiYong]

Where did you buy this phone?

It looks like the phone is still locked to one service provider.

Again, what is the MMI code *121# supposed to do?

[rolle_f]

I had the exact same problem but I live in sweden. My solution was to send the phone for service and I got a new one.

It could be something wrong with the SIM-card reader.

[lloydchronus]

Same problem have you fix yours ?

[M425]

I have a Sony m4 aqua.last some days I saw that my phone have a mmi code problem .when I found this problem I reset my phone.but still I found mmi code wrong in my phone.how can solve this type of problem ? I live in Bangladesh.

[Loverly24]

How to set my experia z4 from 3G to 4G? 

[Uliwooly]

@Loverly24

Do you have an Xperia Z4 Tablet? or a Z3+ ?