No matching SSH algorithm
Client and server cannot agree on a host-key, key-exchange, cipher, MAC, or signature algorithm.
SSH authorized_keys file not found
The public key was installed in a path the effective sshd configuration or target account does not read.
SSH connection timed out
The client cannot complete a TCP connection to the expected SSH endpoint before its deadline.
SSH security key touch not detected
An ed25519-sk or ecdsa-sk identity is selected, but the FIDO authenticator, middleware, user-presence gesture, or verification step does not complete.
SSH GatewayPorts exposure
A forwarded port intended for local use is reachable from other machines because its bind policy exposes it beyond loopback.
Fix SSH error in libcrypto
The client cannot parse the private key material it was given, often after a CI secret lost line breaks or a key format changed.
SSH PAM authentication failure
Sshd reaches PAM, but one account, policy, module, or session step denies or aborts the login.
Rsync over SSH exit code 23
Rsync completed only a partial transfer because at least one file, attribute, path, or remote operation failed.
SFTP or SCP fails over SSH
Interactive SSH works, but file transfer fails because its subsystem, path, permissions, shell output, or protocol assumptions differ.