postfix or exim for high voluem email ?

[Stanley Ukadike]

@twisted1919 It generates a message id as it is clearly visible in the header as "somelongstring@sendingdomain.com". I can't help but notice you said it should save "most of the time". Which means there are times when it doesn't save. What conditions influences such? Would be nice to know so I can debug the issue.

 

[twisted1919]

@Stanley Ukadike - The only reason why a message could not be saved is because of a database failure in order to save the message.
Can you show me some headers from an email to see how it generates the message id header?