Apache2 Ubuntu Default Page

I rebooted my server last week and now the front end no longer comes up. Instead, I’m greeted with the Apache2 Ubuntu Default Page. I’ve tried walking through the installation guide for Ubuntu 16.04/ Apache and doing just the web server related stuff, but to no avail.

Is there a way to delete all of the Apache2 settings and start fresh from that aspect? I’m still getting email alerts, so I imagine LibreNMS is still doing its job in the background just fine.

Or are there instructions available for backing up the important bits and migrating to a new server?

Any help would be greatly appreciated.

Edit: To add to the confusion, the 404 pages are being generated by nginx.

It appears that nginx somehow got installed on my server and was conflicting with Apache.

systemctl stop nginx seems to have fixed it temporarily.

Edit: sudo update-rc.d -f nginx disable fixed it permanently.