VOIP Fritzbox after Sophos XG

Hello, 

i've got a  question about the configuration of my VOIP communication. 

Today i've got a new modem so my configuration is now like: 

Vigor 130 (DSL modem) --> nic1 of Sophos XG firewall --> NIC2 --> Internal Network --> Fritzbox (Voip Server). 

But i have very big problems with my phones. There is no outgoing connection. 

What Rules should I create in my Sophos Firewall XG? 

Thanks a lot for helping me