ERR_CONNECTION_CLOSED: The server closed the connection unexpectedly
Also searched as: net::ERR_CONNECTION_CLOSED · connection closed unexpectedly
Is ERR_CONNECTION_CLOSED happening on your domain?
Repeated external probes can show whether the error is publicly reproducible. Pair that result with request and proxy logs before attributing the cause to connection reuse.
Free, no signup. Runs from outside your network, which is the only way to tell a server fault from a local one.
Short answer
The browser's connection was closed before it received a complete HTTP response. This can involve the origin, a proxy, a load balancer, or network infrastructure; connection reuse and timeout settings are common areas to investigate.
What ERR_CONNECTION_CLOSED means
Unlike an HTTP error response, the browser did not receive enough data to process a completed response. Compare server, proxy, and CDN logs for the same request window to identify which component ended the connection.
Causes and fixes, most likely first
A keep-alive timeout on the server is shorter than the proxy's, allowing a proxy to reuse a connection the server has already closed.
Compare the configured timeouts across the origin and proxy, then set values that are compatible with the documented behaviour of both components.
The worker process was recycled mid-request.
Check worker recycling settings (max requests, memory limits) and enable graceful shutdown so in-flight requests finish.
How to stop it happening again
- •Document and review timeout settings across each hop, including CDN, load balancer, and origin.
Frequently asked questions
Why does the error only happen on repeat visits?
A repeat-visit pattern can point to reuse of a connection that an upstream component has already closed. It is a useful hypothesis, not a diagnosis by itself; confirm it with proxy and origin logs and timeout settings.