We currently have a known issue with error 56 being returned in some circumstances; this is due to the server not knowing an HTTP/1.1 connection has gone stale, and so it attempts reuse and immediately fails. This usually happens when there’s light traffic to a server with more than 5 minutes idle time between requests.
It’s safe to immediately retry - you will get a fresh connection and the request should succeed.
We should be addressing this on the developer server later this week.