Zabbix "failed to send email"

[humroben]

I initially setup zabbix to monitor my Ceph environment and to integrate with my Grafana instance. I had recently seen an issue with Ceph, and immediately started configuring triggers and the mail configuration. At present, the triggers work, and the monitoring is working as expected, however, I keep getting the following error when Zabbix attempts to send mail:

failed to send email: Failed binding local connection end: bind failed with errno 99: Cannot assign requested address

Here are my current email settings:

SMTP Server: mail.citypaine.com
SMTP Port: 587
SMTP Helo: zabbix.citypaine.com
SMTP Email: [email protected]
Connection Security: StartTLS
SSL verify peer: yes
SSL verify host: yes
Auth: User + Pass
<valid auth details>

I've already tested TLS using OpenSSL from the zabbix server, and this succeeds:

# openssl s_client -connect mail.citypaine.com:587 -servername mail.citypaine.com -starttls smtp
CONNECTED(00000003)
...
Timeout : 7200 (sec)
Verify return code: 0 (ok)
Extended master secret: no
---
250 HELP

The mail server in question, is one that I've setup myself, and I can confirm that the Zabbix system is not attempting a connection to it.

Any help on this would be appreciated.

[humroben]

Ignore this, I found my problem. There was an error in the "SourceIP" in the zabbix_server config file.