552 Application Unreachable

The HTTP 552 Application Unreachable status code is an unofficial server error specific to Akamai Enterprise Application Access (EAA), returned when the connector cannot reach the origin application server.

Table of Contents

Usage

Akamai EAA returns 552 after the user has completed Authentication and the data POP forwards the request to the enterprise connector, but the connector fails to establish a connection to the application server. The request never reaches the origin.

The connector sits inside the enterprise network and communicates with internal applications using the IP address or FQDN and port configured in the EAA application definition. A 552 indicates one of these conditions:

  • The origin server IP or FQDN is incorrect or has changed.
  • The configured port is not listening on the origin server.
  • A firewall between the connector and the origin blocks the connection.
  • The origin server is down or unresponsive.
  • The EAA health check for the application is failing, causing the connector to mark the backend as unavailable.

SEO impact

Search engines treat 552 responses as server errors. Persistent errors cause crawlers to reduce crawl frequency and eventually drop affected URLs from the index.

Example

A client requests an internal application through EAA. Authentication succeeds, but the connector cannot connect to the origin server.

Request

GET /api/reports HTTP/1.1
Host: app.example.re
Cookie: akamai_eaa_session=eyJhbGciOiJSUzI1...

Response

HTTP/1.1 552 Application Unreachable
Content-Type: text/html
X-Akamai-Error-Code: 552

<html>
<head>
<title>Application Unreachable</title>
</head>
<body>
<h1>552 Application Unreachable</h1>
<p>The application is not reachable from the
connector.</p>
</body>
</html>

How to fix

Verify the origin server IP address or FQDN and port in the EAA application configuration. Open Application > Server Settings and confirm the values match the actual origin.

Test connectivity from the connector host to the origin:

curl -v http://10.0.1.50:8080/health

Replace the address and port with the values from the EAA application definition.

Check firewall rules between the connector and the origin server. The connector must reach the origin on the configured port without restriction.

Confirm the origin server process is running and listening on the expected port. A stopped service or a port conflict produces 552.

If EAA health checks are enabled for the application, a failing health check causes the connector to stop forwarding traffic. Temporarily disable health checks in the application's advanced settings to determine whether the health check endpoint itself is the issue.

Redeploy the application in EAA after making configuration changes. Changes to the server IP, port, or connector assignment require a fresh deployment to propagate.

Takeaway

The 552 Application Unreachable status code is an unofficial server error specific to Akamai EAA, returned when the connector cannot reach the origin application server. The fix involves verifying the origin IP/FQDN, port, firewall rules, and health check configuration in the EAA management portal.

See also

Last updated: March 6, 2026