Nothing appears.
WHAT TO ESTABLISH
What the browser actually shows: an error page, a timeout, a certificate warning, or nothing.
Each points somewhere different.
CHECK IN THIS ORDER
Is the domain expired? Do the nameservers point at your hosting? Is the account suspended or over quota? Is the site's folder in the right place? Is there a server-level problem?
THE EXPIRY CHECK FIRST
An expired domain explains everything, and nothing else will fix it.
Check the registrar.
THE NAMESERVER CHECK
If they point elsewhere, the domain is not reaching your hosting at all.
THE SUSPENSION CHECK
An unpaid invoice or an abuse issue suspends the account.
Check your billing and your email.
IF THE DOMAIN RESOLVES BUT NOTHING LOADS
Check that files exist in the document root Check the error log
IF OTHER SITES ON THE SAME ACCOUNT WORK
The problem is specific to that site.
IF NONE WORK
Open a ticket.