Having some issues - "Home Assistant had trouble connecting to the server."

I have had my HA server up and running with no issues until tonight in which I’ve made no changes at all. I use letsencrpyt and DuckDNS to run my server, however when I try to connect I get this error:

Home Assistant had trouble connecting to the server.

I commented out the

http:

component and it worked fine connecting via local IP at port 8123. Could my ISP have blocked me from forwarding port 443 (@8123)?

Edit: This is very odd, it allows me to connect to it via a cellular device that’s not connected to my network. I’ve never had this issue before, what gives?

Edit 2: I use merlin for my Asus router software and was using merlin’s NAT Loopback and that seemed to be the issue. I changed from Merlin to Asus and the issue is resolved now.