I have recently noticed that some mail messages generated from the Contact Us form on my sites are going missing - I have found messages through the "View Messages" option while logged in as administrator that seem never to have appeared in the configured email inbox - they don't appear to have been eaten by my spam filters, and I can find no trace of them.

I have received emails that have been created both before and after the missing messages, so I don't think the feature configuration is at fault.

Can you advise on what I should look for to try to identify the problem?  Which log files should I examine?

Regards

Chris