Why a website isn't loading, and how to find out
Work through the layers in order, from the domain name to the page itself. Each layer has a clear symptom in the checker and a usual fix.
Open the tool: Website Checker
1. DNS: does the name point anywhere?
If the checker reports that the domain doesn't resolve, check that the domain hasn't expired and that its A record points at your server. After a change, DNS can take up to a day to reach everyone; our DNS checker compares resolvers around the world.
2. Connection: is the server answering?
A timeout means packets aren't getting through: the server is off, overloaded or a firewall drops traffic. Connection refused means the machine is up but no web server is listening, so restart nginx, Apache or your app.
3. HTTPS: is the certificate valid?
Expired certificates are the most common cause of sudden warnings. Renew it, check that auto-renewal works, and make sure the server sends the intermediate certificate as well.
4. Application: what status comes back?
A 5xx status means the web server is fine but your site's code or database failed: read the error log. A 404 on the home page usually means the document root or rewrite rules are wrong after a deployment.
5. Redirects: does the address end where it should?
Too many redirects usually come from two rules fighting, for example a CDN forcing HTTP while the server forces HTTPS. Pick one place to redirect and make the final address the canonical one.