Really there so many things it could be its hard to offer advice. Here are a few things
Check the DNS. do “dig yourdomain.com” from the server, from your home machine, from other DNS checkers online. Do they all agree. Do they all point to your server public IP address. You don’t give us your domain name, so we can’t check it ourselves.
Check the path on your server, check the domain name is spelt correctly. Typos can happen to all of us.
Try adding a phpinfo.php file in your web root and loading it? If it doesn’t load maybe the path is wrong. If it does load it might give you info about the problem.
Look in the website configuration page. Check the settings there. Try changing them. Try rebuilding the domain.