Can only access Onlyoffice on Nextcloud Snap through LAN: "ONLYOFFICE cannot be reached. Please contact admin" when accessing through external domain

Nextcloud version 20
Operating system and version Ubuntu 20.04
PHP version 7.3.18

This is nextcloud snap installed on an Ubuntu 20 VM hosted on Proxmox. I set up onlyoffice for online file editing of word/excel files etc. and it works great when I access through lan (nextcloud.localnet) but NOT when I try to use onlyoffice through my external domain ( not my actual address

I installed “ONLYOFFICE” 4.30 and the “Community Document Server” 0.1.7

I can otherwise access Nextcloud through my domain on https without a problem and it has certs generated with LetsEncrypt.

This does not pop up in my nextcloud admin/logging

I’m not sure where to find the Apache/nginx/system logs for a snap installation, I’ll provide when I figure that out/get some guidance.

I have the same problem, although on CentOS. But only accessible on LAN. As soon as I use my domain name it will not load.

My only office has stopped working as well, on nextcloud 19/stable, ubuntu 18.04 server on digital ocean.