558 Connection Limit Stop

The HTTP 558 Connection Limit Stop status code is an unofficial server error specific to Akamai Enterprise Application Access (EAA). The platform returns this code when a user exceeds the service concurrent connection limit.

Table of Contents

Usage

Akamai EAA enforces per-user connection limits to protect backend applications from resource exhaustion. The 558 error appears when a single authenticated user opens too many simultaneous connections to a service, particularly WebSocket connections.

The default limit is 50 concurrent WebSocket connections per user. This cap prevents individual users from monopolizing connector resources and guards against connection-based attacks. Standard HTTP request-response cycles are less likely to trigger this limit because connections close after the response completes. Long-lived connections like WebSockets accumulate and reach the threshold faster.

Rate limiting applied to the connecting IP address also triggers a 558 when the volume of requests from an authenticated user's IP exceeds the configured threshold.

SEO impact

Search engines treat 558 responses as server errors. Persistent errors cause crawlers to reduce crawl frequency and eventually drop affected URLs from the index.

Example

A client opens multiple WebSocket connections through Akamai EAA to a real-time collaboration service. After exceeding the concurrent connection limit, the next connection attempt receives a 558.

Request

GET /ws/collab HTTP/1.1
Host: app.example.re
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Version: 13
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==

Response

HTTP/1.1 558 Connection Limit Stop
Date: Mon, 02 Mar 2026 14:35:00 GMT
Content-Type: text/html

<html>
<head><title>558 Error</title></head>
<body>
<h1>Connection Limit Stop</h1>
<p>Service concurrent connections exceeded</p>
</body>
</html>

How to fix

Reduce the number of simultaneous connections from a single user session. Applications opening multiple WebSocket connections in parallel (tabs, microservice fan-out, real-time feeds) need connection pooling or multiplexing to stay within the 50-connection limit.

Close idle WebSocket connections. Applications opening connections without properly closing them when no longer needed accumulate stale connections against the per-user limit. Implement heartbeat timeouts and close connections no longer sending or receiving data.

Review the application architecture. A single WebSocket connection carrying multiplexed messages replaces multiple individual connections. Protocols like Socket.IO and GraphQL subscriptions support multiplexing over a single transport connection.

Contact Akamai support if the application legitimately requires more than 50 concurrent connections per user. Custom limits are available for specific deployment scenarios.

Check for connection leaks in the client-side code. Browser developer tools and network monitors reveal open WebSocket connections the application failed to close during navigation or component teardown.

Takeaway

The 558 Connection Limit Stop status code is an Akamai EAA error enforcing a per-user cap on simultaneous connections, with a default limit of 50 WebSocket connections. Reducing parallel connections or multiplexing traffic over fewer connections resolves the issue.

See also

Last updated: March 6, 2026