Using Jabber-Messaging on my own prosody does not work.
The server-log shows

8134:20160519:192508.181 JABBER: [USER@SERVER] tls handshake failed

Debug-log of prosody:

May 19 18:25:01 socket debug starting handshake...
May 19 18:25:01 socket debug ssl handshake of client with id:table: 0x324ee0d3c0, attempt:1
May 19 18:25:01 socket debug ssl handshake of client with id:table: 0x324ee0d3c0, attempt:2
May 19 18:25:01 socket debug ssl handshake error: unknown protocol
May 19 18:25:01 socket debug closing client with id: 324ee0d3c0 unknown protocol
May 19 18:25:01 c2s324ee150e0 info Client disconnected: unknown protocol

Attached a screenshot of the handshaked.

For me it seems that Zabbix is only trying TLSv1.0. My prosody is configured to allow TLSv1.1 and TLSv1.2 only and I do not want to allow TLSv1.0

ssl = {
options =

Unknown macro: { "no_sslv2", "no_sslv3", "no_tlsv1", "no_ticket", "no_compression", "cipher_server_preference", "single_dh_use", "single_ecdh_use" }

;
key = "certs/privkey.pem";
certificate = "certs/fullchain.pem";
dhparam = "/etc/prosody/dh-2048.pem";
ciphers = "DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:DHE-RSA-CAMELLIA256-SHA:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES256-SHA";
}