Our servers only currently block emails with invalid senders from a few large domains at this time; GMail and Yahoo are two of the larger domains affected. This list will expand as time goes on.
With regard to your help desk software, I do understand how that could be an issue. I'm not familiar with Track-It, but I can't imagine you're the first user to encounter this sort of issue. Please contact BMC support to see if there's an alternate solution available for this.