No internet access in WIFI

Hello community,

we are using a Sophos XG 310 for quite some years now. 

Since the beginning we had two WIFI's configured. One with Bridge to AP LAN and one as Separate Zone with Hotspot system.

I never had to create a special firewall rule to get internet access from on of the WIFI's.

Now I wanted to create a third WIFI as Separate Zone with WPA2/Personal. The WIFI itself works and the so does the DHCP. I can successfully connect to the WIFI but I don't have internet access there.

I followed the instructions from Sophos to create a WIFI and also tried to add the firewall rule from WIFI to WAN. But its still not working. 

Maybe someone can point me in the right direction what I am missing ?

Thank you

Ben