ERR_CONNECTION_RESET: The connection was reset mid-transfer
The connection was established and then abruptly torn down before the response finished. Usually a crashing worker process, a proxy timing out, or middleware killing the connection.
Short answer
The connection was established and then abruptly torn down before the response finished. Usually a crashing worker process, a proxy timing out, or middleware killing the connection.
What ERR_CONNECTION_RESET means
A reset means a TCP RST arrived after the connection was already open. Something decided mid-flight to abandon it — which points at the application crashing, a proxy giving up, or a network device interfering.
Causes and fixes, most likely first
The application process crashed while generating the response. Read the application error log at the timestamp of the reset. An out-of-memory kill is the most frequent culprit.
A reverse proxy or load balancer hit its timeout and severed the connection. Raise the proxy read timeout, or make the slow endpoint faster. Match the proxy timeout to the application's real worst case.
A firewall, ISP filter, or DPI device is resetting connections. Test from another network. Consistent resets on one network and not others point at a middlebox rather than your server.
How to stop it happening again
Alert on intermittent failures, not just sustained outages — resets are usually a minority of requests and easy to miss.
Keep proxy and application timeouts aligned so neither cuts the other off.
Check your own domain
A probe from outside shows whether the reset is reproducible for everyone and whether it happens consistently or intermittently.
Frequently asked questions
Why is the reset intermittent?
Because it usually tracks load or a specific slow request path. Correlate the failures with request duration and memory usage rather than treating them as random.