Salmon returns error 417
I'm working at the OStatus implementation of Friendica. The current state is that the communication mostly work great. But sometimes there are issues.
When trying to send a salmon notification to quitter.is (which is running version 1.2.0-beta2) I always get the HTTP error 417. With other servers (even with the same version) it seems to work. What does error 417 tell me?
I'm not sure if this really is a thing for an issue - but maybe this points to a general problem since users from that server say that they seem to have communication problems.