My forum was good till today morning I noticed that the home page has somehow been replaced my apache default page.It has disappeared or at least got hidden.
Did you restart the server? Do you need apache installed on the server or are there other sites/admins who might need it installed?
If it’s not needed, I’d recommend uninstalling apache and restarting your discourse instance. apt-get remove apache2, cd /var/discourse (or where your discourse install is) and ./launcher restart app