I’m having trouble reaching my discourse site. I was in the process of moving it to a new domain, but stopped and undid my changes and it hasn’t come back up. I followed this thread to change the domain and then undid everything in reverse order.
Checking your domain name . . .
WARNING: Port 443 of computer does not appear to be accessible using hostname: 443.
WARNING: Connection to http://443 (port 80) also fails.
This suggests that 443 resolves to some IP address that does not reach this
machine where you are installing discourse.