Nextcloud working on local network, but timeout when connecting externally

Hi all, thanks for reading in advance, I’ll try to make it quick:

I’ve set up Nextcloud from scratch on a LAMP stack on OpenSuse Tumbleweed. Everything works fine when connecting from LAN, but when I try to connect from the internet (via domain name or IP) I don’t even get to the login page. There is a connection, but nothing loads.

I’ve been able to narrow it down to php-cURL–with it disabled I get the “Nexcloud technical issue” warning immediately. But that’s such a core module, I’m not sure what to make of it.

I’m hoping it’s just some stupid mistake since it’s been a while since I’ve last worked with Apache.
Happy to post any config files or error logs… and thanks for any tip or help!

Here’s my vhosts.d config:

<VirtualHost *:80>
  ServerAdmin admin@xxxx.yyy
  DocumentRoot /srv/www/htdocs/nextcloud/
  ServerName  x.yyyy.zzz

  Alias /nextcloud "/srv/www/htdocs/nextcloud"

  <Directory /srv/www/htdocs/nextcloud/>
    AllowOverride All
    Options FollowSymLinks MultiViews
    Require all granted
      <IfModule mod_dav.c>
        Dav off
    SetEnv HOME /srv/www/htdocs/nextcloud
    SetEnv HTTP_HOME /srv/www/htdocs/nextcloud


EDIT: I’m using a DDNS service to register my domain name to my home IP, but since simple test HTML files (and the Nextcloud error messages) work I doubt the issue lies there.