email issues and IP address for firewall whitelisting

[davidrb84]

Hi,

I'm drawing a blank on an issue causing only some of our emails to be undeliverable via our smtpserver.

Does anyone have any suggestions of places to look? 
Logs are not helping me so far.

Related to looking at it, I know all the connections to our smtpserver will be coming from 1 IP, what is that IP? (I've had it before but can't find it!)

 

Example partial log output for a given failed email (sitting in outbox)

2024-11-21 10:33:39	Connecting to: XXXXXX.XX.ac.uk, Port: 587, SSL: no, STLS: yes
2024-11-21 10:33:40	Failed to deliver message to target recipient.
2024-11-21 10:33:40	Unable to connect to SMTP server. Chilkat: ChilkatLog: VerifySmtpLogin:

server name/domain XX'd out intentionally for this post.
The ChilKat , ChilkatLog, VerifySMTPLogin elements all blank for this log entry.

Anyone any ideas?

[Graham]

@davidrb84 See Hornbill Cloud - Firewall IPs and Ports for the source IPs.