Problem

You receive an unclear error message like the following in your trace files:

transient failure connecting to remote: Success. SSL system call failed

Resolution

This may happen when there's a connection timeout to an HTTPS endpoint. OpenSSL returns a code of zero, which converts to "Success" when stringified because there were no SSL errors. A failure to connect happens before SSL even begins, so it does not report that as a failure even though the connection expired without the remote endpoint responding at all.

This sort of failure may happen due to firewalls on the remote end of the connection that whitelist which IPs are permitted to connect to it. You can try to connect to the host from other IPs, if available, to rule out connection errors, and do other tests to ensure that the endpoint responds to traffic. In general, something like this will require assistance from whoever maintains the endpoint you are trying to connect to as it is not, in general, possible to pinpoint why the other side is not responding to a connection attempt without knowledge of what's happening on the remote endpoint and any firewalls in front of it.