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This section describes common CDN setup issues and how to resolve them.

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503 service unavailable

This error means that the CDN cannot reach your origin server. Possible causes:
  • The origin server is not accessible.
  • The origin blocks CDN IP ranges.
  • The origin port is incorrect.
  • The resource has not been fully propagated yet.
Solution:
  • Verify that the origin server is accessible directly (for example, via browser or curl).
  • Allow CDN IP ranges in your firewall settings.
  • Confirm that the correct origin port is configured (80 or 443).
  • During initial setup, propagation can take up to ~20 minutes. Wait for resource propagation to complete, then retry the request.
For more details, see 5xx error: how to solve server issues.

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ERR_TOO_MANY_REDIRECTS

This issue occurs when both the CDN and the origin enforce redirects, creating a loop. Possible cause:
  • Both CDN and origin redirect HTTP to HTTPS.
Solution:
  • Disable the redirect on either the CDN or the origin side.

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Website downloads as file

This behavior indicates incorrect response headers from the origin. Possible cause:
  • The origin returns an incorrect Content-Type header.
Solution:
  • Check and correct MIME type configuration on the origin server.

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SSL certificate errors (Let’s Encrypt)

SSL issues are often related to DNS configuration and certificate validation. Possible causes:
  • DNS changes have not fully propagated.
  • Let’s Encrypt cannot validate the domain.
Solution:
  • Wait for DNS propagation to complete (up to 24–48 hours).
  • Retry certificate issuance after propagation.
For more details, see An SSL certificate isn’t working: how to solve.