Little problem with external IP

Hi everyone !
I have just installed nextcloud, configured it and I have a problem. I have installed it in but. I have an access to the log in page when I use the local IP to connect (192.1…/nextcloud) but when I use my 4G to connect it I have the page (ubuntu server, it works!) So the ports are open (443 and 80) but when I go to the nextcloud page I have "the connection was reset… could you help me ?
Thanks a lot

Hi Jules,
You may need to access your server by ssh and disable the default pages (sudo a2dissite 000-default.conf) that will stop the default page showing. Secondly, check your apache2 configuration for your nextcloud install. You should have in the configuration file the ServerName directive. It should read ServerName
That way when you browse to your domain, it should find it (providing you have set the DNS records for associating your ipaddress with your domain correctly)
Then your site should work with the following
I hope this helps,
Edit… when I navigate to your site it works.