Ok, we've got a partial victory ... Unreal is running!! (again!) I tried literally everything, and after just googling a bunch of stuff (because I truly don't want to keep messaging you all day for fear of burning you out, when I know I'm gonna really need you on much bigger stuff later ...) These are the commands I found that worked:

sudo chgrp -R ssl-cert /etc/letsencrypt
sudo chmod -R g=rX /etc/letsencrypt

I had a hunch that it had something to do with the ssl-cert group not having the right permissions, so I googled that, and that's what led me to the above commands which "let me in" so to speak.

All that said, don't release the balloon drop just yet ... the chatbox is still greyed out, with the same link inside it.

This is what sudo ls -l gives me: chatuser@redditclone:~/unrealircd$ sudo ls -l /etc/letsencrypt/live/portcity.online/fullchain.pem lrwxrwxrwx 1 reddit ssl-cert 44 Jul 20 01:48 /etc/letsencrypt/live/portcity.online/fullchain.pem -> ../../archive/portcity.online/fullchain1.pem