SOLVED: Unable to connect to Jellyfin on the same network, using remote DNS entry

[TheDreadPirate]

Check if your router supports NAT loopback/NAT hairpin and enable it. The router will loop back all requests to your domain since the address resolves to itself instead of your requests going out to the Internet.

Also try incognito mode and see if it still happens.

I will do some testing when I get home later tonight.