Password recovery email not sent from puplic ip

I just rebuilt my entire freenas installation using 11.2
As part of this I installed nextcloud 15.05 in its own jail - more or less following Samuel Dowling’s instruction (…n-freenas-iocage-jail-with-hardened-security/)
Skipped parts of the “hardening” where I opted for a self signed cert since I don’t have a domain

nc Server runs, can connect using local IP as well as my exposed IP via ssl.
As admin I can send out a test email using both the local and public ip address.
BUT! I can’t send out a psw recovery email using the public IP.
It works flawless using my internal IP, but nothing is sent out when accessing nc using the public IP.
The mailer log shows this…
Mar 31 16:30:00 nextcloud sendmail[71088]: x2V8U089071088: from=www, size=520, class=0, nrcpts=1, msgid=<>, relay=www@localhost
Mar 31 16:30:00 nextcloud sendmail[71088]: x2V8U089071088: to=www, ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30520, relay=[] [], dsn=4.0.0, stat=Deferred: Connection refused by []

Nextcloud.log don’t show anything even though I turn on full debug for both smtp and nc itself inside the config.php

can’t figure out whats going on with this???

mail config within nc:
Send Mode: smtp
Encryption: STARTTLS
Authentication: None
Auth Method: None
Server address: smtp.<my isp mail domain>
Port: 587 also tried 25 & 465

Any suggestions?

You are relaying mails to your mailserver on localhost ( which refuses to forward the mail. You could use ssmtp or similar software to forward such mail or directly authenticate and send through an external mail server.