Windows Fax and Scan only works with attachment

Hello,

I used the Fax Server step by step set up guide to configure windows fax and scan on my windows server 2012 machine. When I try to send a fax I'm getting error "The message could not be sent. The wait operation timed out" When I attach a .txt file or a .rtf to it I'm able to send the fax just fine. Any ideas what I need to do to correct this issue?

Thanks.