Are you sure you followed the Official Installation Guide? It says Digital Ocean but any Ubuntu VPS will do.
Also are you using Discourse from Bitnami? The Discourse community can only support the official installation that I linked above (NOT the Bitnami version).
You must have another apache server in your environment that is interfering if you followed the Official Install Guide. The official guide installs a built in nginx server that is ready to use assuming you followed the guide correctly. Is there a custom setup in your environment?
If you have Apache and know how just disable it (for this site only). The Official Install uses a Docker image with nginx (a web server) preloaded and ready to use. All you have to do is visit the site after disabling apache and it should work
If the VPS has an A record pointed properly (per Install Guide) it should work. If you can and it really doesn’t work delete/reset to new the VPS and follow only the steps in the install guide.
Also make sure that ufw and similar programs are either disabled or allow ssh, http and https (if you want https) through from your IP
Its not recommended to use any 1 click installers (even Digital Ocean ones). Just by searching on this site you can see examples of weird errors and behaviour that doesn’t exist in the Guide’s version. Its ultimately up to you but you often need to pay more (Discourse will work on a 1GB droplet if you follow the Official Install Guide) to make a 1 click installer work.