I'm not sure where to go with this problem. I have a single internal Exchange 2010 mailbox address, lets call it randy@mydomain.com, that cannot receive email from a specific outside gmail address, lets call it carrie@theirdomain.com. All other external email addresses are received by randy@mydomain.com. All other internal email addresses can receive email from carrie@theirdomain.com. This company does not have a 3rd party mail filter. The email is not going to thier junk box. I ran a query on the Exchange server using the Tracking Log Explorer and noticed that every email from carrie@theirdomain.com to randy@mydomain.com has a blank entry in the recipients column. I had her CC me on an email to my user and the address is correct. The sender isn't using outlook so it's not a bugged .n2k entry. I checked the mail delivery options on my user's mailbox and it set to receive all email. I'm lost on this one. Any troubleshooting advice?
Edit: I forgot to add that they use ESET for their mail server AV. There are no traces of the emails from this sender being pruned by it.
