Aug 13 13:46:33 s2sout2d45040 info Failed in all attempts to connect to proxy.eu.jabber.org
Aug 13 13:46:33 s2sout2d45040 info Sending error replies for 1 queued stanzas because of failed outgoing connection to proxy.eu.jabber.org
No clue why it tries to use a proxy not explicitly specified. This could be because the proxy specified for the domain fails when someone is trying to send a file. I wish this could be disabled for security reasons in prosody.