According to Microsoft, this error may be recorded when the Fax service on a Windows 2008 Server is configured to route the faxes to an email address. The full description of the problem and information about the hotfix available can be found on ME973640
I have found that McAfee VirusScan Enterprise 8.0's port blocking feature will cause this error message. It will only prevent connections from port 25 to port 25 on the same computer, so other e-mail functions will appear to work. Disabling this port blocking rule from the VirusScansís Console solved the issue for me.
In my case, port 25 was blocked by the firewall. I added fxssvc.exe to the exception list for port 25 and the problem was solved.
From a newsgroup post: "You might try to following:
1. Open Server Management.
2. Right-click on Fax (Local) container.
3. Select "Properties".
4. Select "Receipts" tab.
5. In the Message Box, enable the "Enable Message Boxes as receipts" checkbox.
6. In SMTP E-mail, check the following:
a. "Enable SMTP Receipts e-mail receipts delivery" is enabled.
b. "Use these SMTP Settings for the Route through E-mail incoming routing method" is enabled.
c. Under Authentication, try setting to Anonymous access if not set already".