Mobile data connection fails but wireless connection is OK

[Hosseinzt]

Hi

My Xperia M dual always works on wireless connection but over mobile data (EDGE) it fails and my internet setting in APN become lost. Only restart my phone makes it work again with my mobile data connection. After using wireless internet for some times, mobile data connection fails again.

Please help me

[Uliwooly]

you probably don't have the correct APN settings 

or 

the SIM card its too old

or 

the SIM card its faulty 

or 

there's an app acting up, it could be a taskiller, antivirus, ram apps, etc 

[Hosseinzt]

I don't have problem with my previous device Xperia E dual. If Sim is old why it worked before?
How should l find the app which make this problem?

[Uliwooly]

reboot on safe mode

http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008

[Hosseinzt]

my sim card works well on the other devices like Xperia E Dual.
What does reboot do ?

[Hosseinzt]

Lt seems the problem be solved. l change my mobile mode setting to GSM only mode. Data connection now works well but still testing...