When a site goes down, the quickest fix comes from checking things in the right order rather than changing settings at random. This checklist starts with the cheapest checks and links to a detailed guide at each step.
Before you start
- Write down what you see: the exact error message or code, which pages fail and since when.
- Think about what changed recently: a plugin update, DNS edit, PHP version switch, new SSL, domain renewal.
Is it down for everyone?
- Open the site in a private window and on mobile data (Wi-Fi off).
- If it works on mobile but not at home, your IP may be blocked by the firewall or your local DNS is stale. Check your IP with the IP checker and flush DNS.
Check the domain and DNS
Errors like server IP address could not be found mean DNS. Check the domain hasn't expired with the WHOIS checker, then follow Domain not resolving.
Check SSL
Your connection is not private or NET::ERR_CERT errors mean a certificate problem, not downtime. See Fix common SSL errors and AutoSSL not working.
Read the error code
A numbered error (403, 404, 500, 502, 503, 504) tells you which layer failed. Match it in Website error codes explained. A blank white page is covered in WordPress white screen of death, and "Error establishing a database connection" in its own guide.
Check resources and disk space
- Open cPanel → Metrics → Resource Usage. Recent faults for CPU, memory or entry processes mean the site hit its limits; see 508 Resource Limit Reached.
- Look at disk and inode usage on the cPanel home page sidebar. A full account can't write sessions or cache; see inodes and quota limits.
Undo the last change
- Plugin or theme update: disable it by renaming its folder in
wp-content/plugins. - PHP version change: switch back in Select PHP Version.
- Edited .htaccess: see Troubleshoot .htaccess problems.
- Nothing obvious? Restore yesterday's copy from JetBackup: restore files and restore a database.
Ask support
If the checks don't reveal the cause, open a ticket with the URL, error, time and what you've tried. MdmHost support is human and available 24/7.