I've set up port forwarding on the router successfully with the WAN-side port being 8123, but I can't get port 80 to work.

I've already configured the admin panel port to 8081 to avoid conflicting.

In the diagnostic export I can see that the port is correctly configured:

  127  6612 DNAT       tcp  --  *      *       0.0.0.0/0            24.190.209.70        /* Hassio */ tcp dpt:80 to:192.168.0.3:8123

To test, I also forwarded port 8123 to 8123, and I can curl my ip with port 8123 successfully, however port 80 times out.

Edit: I've also set the host to a DMZ and confirmed that every port I try EXCEPT 80 works fine.