Troubleshooting Cloudflare connections

Get help resolving Cloudflare connection issues, including error pages and DNS configuration problems.

Note

For instructions on activating Cloudflare, see the setup guide. For details on configuring Cloudflare, consult the Cloudflare documentation.

Cloudflare Error Pages

A common sign of connection issues is when Cloudflare displays an error page instead of your site. These pages can indicate why your site isn’t loading properly.

Common Error Pages:

520 Web server is returning an unknown error: Details
521 Web server is down: Details
522 Connection timed out: Details
523 Origin is unreachable: Details
524 A timeout occurred: Details
525 SSL handshake failed: Details
526 Invalid SSL certificate: Details

Site DNS Settings

Cloudflare requires your domain’s nameservers to route traffic through their network.

Note: If connection issues appear within 24 hours of enabling Cloudflare, wait for DNS propagation to complete.

A blank browser page (white screen of death) usually indicates an issue with your site or server—not Cloudflare.

Verifying DNS Configuration

Log in via SSH.
Run the following command (replace example.com with your domain):
```
dig www.example.com
```
In the output, check the AUTHORITY SECTION:
- If a hostname containing cloudflare.com appears (e.g., dns.cloudflare.com or ns.cloudflare.com), your DNS is configured correctly.
- If not, your domain isn’t using Cloudflare.

You can also use dig or nslookup on your local computer to query www.example.com.

If cloudflare.com appears, your DNS settings work along the path from your computer to Cloudflare and your server.
If not, the issue is likely with your local network or computer configuration.

More Information

For additional Cloudflare resources, visit https://www.cloudflare.com.