Thanks @Calby, though like I said, everything is functioning internally on LAN. I just can’t get the WAN piece working.
It appears that though my router has Port Forwarding set to pass 443 traffic to my seafile server, it’s not doing it. It’s stopping the traffic at the router and prompting to login to the router. I have a Netgear Nighthawk R7000.
I have other port forwards working, but seafile is the only one I’m opening for 443. Not sure if it’s a router setting, or something in the nginx config.