Default Phone does not work after modem update CM11

Hi guys,

i updated my I9505 on modem I9505XXUGNE5 - i have vodafone.de as provider - after that, i cant make any phone calls.
I can call or beeing called - phone rings - but the screen somehow hangs...and cant be heard of the caller / the guy i called..

Any ideas whats going on? Got CM11 Snaphot on it.

Thanks in advance guys!

Cheers
Simon