I'm having an issue that I cannot seem to get through. There is email from one external sender that just seems to never make it though to our user's inbox. We have a barracuda firewall for email and it shows as passing through and being delivered. In ECP, I've done a message trace and it shows that the email was delivered to the user's inbox. I have thoroughly scoured the account and there is no email from the sender, not in inbox, junk, deleted, etc.
I've done everything I know to do at this point, any help would be appreciated.