Hi Victor,
Additional info: configured XMPP account works for some time after server restart, then disconnects from server.
XMPP client installed on my computer shows this particular account as 'disconnected'.
Also I found this in log file:
57941: [03-Dec-2015 20:41:28.504] [DEBUG] XMPP: Unrecoverable TLS error, 5.
57942: [03-Dec-2015 20:41:28.504] [DEBUG] XMPP: Closing socket.
57943: [03-Dec-2015 20:41:28.504] [DEBUG] XMPP: disconnected
57944: [03-Dec-2015 20:41:28.504] [DEBUG] XMPP: Stopping event loop.
58232: [03-Dec-2015 20:41:58.504] [DEBUG] XMPP: sock_connect to jid.pl:5222 returned 23200
58233: [03-Dec-2015 20:41:58.504] [DEBUG] XMPP: attempting to connect to jid.pl
58234: [03-Dec-2015 20:41:58.535] [DEBUG] XMPP: connection successful
Hope this shed some light what can be wrong.
Best regards, Grzegorz.