[Question] DOUBLE SIM DG580

[Rudo]

My DG580 works with two SIM cards but... one SIM is OK for calls and data but the second SIM can be used for calls only. It does not connect to data network and keeps saying No Internet Connection. However in another smartphone it works well.
I understand that double SIM phones can have problems with data connection, is is the case with DG580 too? (For info - one SIM is the Slovak Telekom and the second one is the Austrian A1.)