That should not be possible…your browser should show you the following message, when you try to access
/remote.php/dav/files in your browser:
This is the WebDAV interface. It can only be accessed by WebDAV clients
such as the Nextcloud desktop sync client.
Please can you check if you have the following in your Apache config for your Nextcloud VirtualHost:
RewriteRule ^/\.well-known/carddav https://nextcloud.1io.com/remote.php/dav/ [R=301,L]
RewriteRule ^/\.well-known/caldav https://nextcloud.1io.com/remote.php/dav/ [R=301,L]
Edit: Can you download the Nextcloud Client and see, if this is showing the same behaviour?