I’ve installed Nextcloud 13.0.4 on Ubuntu Server 18.04 with Apache 2.4.29.
I took a domain name from noip.com like [hostname].ddns.net.
Now I can reach Nextcloud from https://[hostname].ddns.net/nextcloud.
How can I reach Nextcloud simply with https://[hostname].ddns.net?
I think you set the wrong Root Directory. You will find the conf in /etc/apache2/sites-available/.
Don’t forget to restart apache after editing the conf with sudo service apache2 restart.