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When I put in my SIM card the phone shows that is has signal, but when I try to make a call it is not going through. I tried entering a service code like *120# for balance of my account and it's saying "connection problem or invalid mmi code" - what's wrong?
2012-12-26 17:13:03
nice suggestion
2012-12-08 07:22:51
This has happened with me when I bought a new SGY. New devices might not be compatible with Older SIM Cards. Your device might not support the older SIM. Buy a new SIM or ask your service provider for a new SIM. Although I don't know why it happens that way, but it surely happens as it happened with me.
2012-12-07 16:45:27
Check if any recent app is installed is causing any problem by going to safe mode -http://www.howtogeek.com/130327/how-to-boot-your-android-phone-or-tablet-into-safe-mode/If you can make calls in safe mode,then the above fact justifies it and then try removing that app.If this doesn't helps,backup your data and factory reset your phone.
2012-12-06 14:30:30
Is your sim card registered???
2012-12-06 12:03:20
try this *100*2#,