Test the site from another connection/device, then check DNS, HTTPS, server status, and application logs in that order.
Step by Step
- Confirm the exact URL and error message.
- Test from another device or cellular connection.
- Check whether DNS returns the expected address.
- Check the HTTPS certificate/connection.
- Check hosting/server status.
- Check the web server or process manager.
- Review recent application/server logs.
- Review recent deployments or DNS changes.
If That Doesn't Work
- A browser error message often identifies the layer that failed.
- Do not make multiple unrelated configuration changes at once; you can make diagnosis harder.