I am having two separate installations (East & West) of different version of Smarter mail and having issues with email delivery.
East - Smartermail 11 (domain.com)
West - Smartermail 14 (domain.net)
SMTP In - relay setting is set to nobody for both the servers.
I am testing delivery from web mail between both the servers and both bounces the message with 550 Authentication is required for relay bounces for domain.com and domain.net that are hosted there. However both these server can send and receive emails from others domain (Yahoo, Gmail, anydomain) without any issues.
However, there are no smtp (Already set to detailed) logs and only delivery logs are available when send from domain.com to domain.net and vice versa. But that is not the case if send email to any other domains.
Appreciate if anyone can share their expertise.
Update - Enabled "Append authenticated as header for outgoing messages" in Protocol Settings-> SMPT Out without any success.