curl Exit Code 56 in CI: Failure Receiving Network Data
curl exit code 56 means a failure while receiving data - the connection was reset or dropped mid-transfer.
A step exiting 56 from curl started receiving a response but the connection broke before it finished.
What it means
Exit 56 is curl's CURLE_RECV_ERROR. A network receive failed - typically "connection reset by peer" from the server, a proxy, or the network dropping the stream.
Common causes
- The server reset the connection (RST) mid-response.
- A proxy/firewall idle-timeout closed the stream.
- Network instability or packet loss.
How to fix it
Add --retry for resilience and check proxy/idle-timeout settings. Connection resets are usually transient infrastructure failures - Latchkey auto-retries this mechanical class rather than failing the run.
Reading exit codes in CI
- A shell reports
128 + Nwhen a process is terminated by signal N: 137 is SIGKILL (usually the out-of-memory killer), 143 is SIGTERM, 130 is SIGINT. - Exit code 137 in a container almost always means the kernel killed it for memory. Nothing in the application log will explain it.
- A pipeline reports the exit status of its LAST command unless
pipefailis set, which is how a failing command piped toteeproduces a green build. - Some tools use non-zero codes for non-failure outcomes. Check the tool documentation before treating any non-zero code as an error.
Frequently asked questions
curl Exit Code 56 in CI: Failure Receiving Network Data?
A step exiting 56 from curl started receiving a response but the connection broke before it finished.
What it means?
Exit 56 is curl's CURLE_RECV_ERROR. A network receive failed - typically "connection reset by peer" from the server, a proxy, or the network dropping the stream.
How to fix it?
Add --retry for resilience and check proxy/idle-timeout settings. Connection resets are usually transient infrastructure failures - Latchkey auto-retries this mechanical class rather than failing the run.
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