Exclamation [Q] Galaxy x cover network failure

After flashing cm 10.1 . i can't call or receive calls, sms or mms. it says NETWORK failure - (name of the network operator)
on lock screen . i installed 20140204_cm_10.2_skomer-ota-eng.flx. to check if this solves the network problem but it didnt !! .

how to fix this !!
PHN : Xcover 2 . GT-S7710