Forward but not Send


New Email
A user in our office is trying to send messages to another user. Some have Excel attachments, some don't. When she clicks on Send, the message seems to go through--it shows up in her Sent Folder and she doesn't get any error message. The receiving user never gets the message. When the sending user pulls up the message in her Sent folder and Forwards it to him, he gets it with no problem. He is the only one having this problem, so I'm wondering if the problem is at his end and not hers, but I can't imagine what it could be. Both are using Outlook 2003, and there is no Exchange server involved, we use Internet mail with our own domain.

Any help would be appreciated!