I host my stalwart-instance behind a Caddy reverse proxy for HTTPS (stalwart listener on port 10443) and use automatic DNS management. This creates entries like this in my zone:
_jmap._tcp IN SRV 0 1 10443 mail.magahugu.ch.
which is clearly wrong: it should be the default HTTPS port 443.
Please add an option in Network/Services/Advertised Services to override the ports.
Stalwart v0.16.8 github build, bare metal on Arch Linux