Contacting license server through a firewall

I run the duplicacy-web docker from saspus on unraid with a fixed IP (custom brigde), hostname and mac address (extra parameters: --hostname=myhostname --mac-address my:ma:ca:dd:re:ss) and everything is working fine.
For security reasons I also run a firewall (Sophos-XG) on a dedicated hardware that’s connected to my local network (lan) and to the cable modem (wan).
To renew the duplicacy-web license it seems that I have to open port 443 from my duplicacy-web docker IP to the WAN.
My question: Can I limit the acces from my duplicacy-web docker to a hostname or an IP address (range?) on port 443 (allow: mydocker => somehostname:443) or do I have to open it to the whole WAN on port 443 (allow: mydocker => *:443).

Our license server also runs on so if you can whitelist it should work.