535 Unknown Project

Unrecognized Host header values not matching any deployed project on Edgio produce the 535 Unknown Project status code.

Table of Contents

Usage

Edgio routed incoming requests to the correct project based on the Host header. Each project registered one or more hostnames (custom domains or *.layer0-limelight.link / *.edgio.link subdomains) during deployment. When a request arrived at an Edgio POP with a Host value not matching any registered hostname, the platform had no target project and returned a 535.

Common causes included:

  • DNS records (CNAME or A) pointed to Edgio IP addresses, but the corresponding hostname was never added to an Edgio project.
  • The project was deleted or redeployed under a different hostname without updating DNS.
  • A load balancer or upstream proxy rewrote the Host header to a value Edgio did not recognize.
  • The request targets an IP address directly instead of a registered domain name.

Example

A client sends a request to an Edgio POP, but the Host header does not match any known project. Edgio returns a 535 error.

Request

GET / HTTP/1.1
Host: unknown.example.re
Accept: text/html

Response

HTTP/1.1 535 Unknown Project
Date: Mon, 02 Mar 2026 14:30:00 GMT
Content-Type: text/html
Server: ECAcc (dce/26A1)

<html>
<head><title>535 Unknown Project</title></head>
<body>
<h1>535 Unknown Project</h1>
<p>No project matches the requested hostname</p>
</body>
</html>

How to fix

Verify the Host header in the failing request matches a hostname registered in the Edgio project. Open the Edgio console, navigate to the project's environment settings, and confirm the domain is listed under custom domains or hostnames.

Check DNS records for the domain. The CNAME or A record must point to the Edgio-assigned endpoint for the specific project environment. Running dig example.re confirms where DNS currently resolves.

If the project was recently migrated to a new Edgio platform version, re-add all custom domains in the new project's configuration. Platform version upgrades do not automatically carry over hostname registrations.

Inspect any intermediate proxies, load balancers, or CDNs sitting in front of Edgio. Confirm they forward the original Host header unmodified. A proxy rewriting the Host to its own internal hostname causes Edgio to reject the request with a 535.

See also

Last updated: August 18, 2026