Odd server return thing

[gr8hunter1 at comcast.net (Jacob)]

I just sent a message off in reply to RE: (OT)I would like to ask you 
all a question...(Long)
And this came back.

Your mail to 'Scirocco-l' with the subject

    Re: (OT)I would like to ask you all a question...(Long)

Is being held until the list moderator can review it for approval.

The reason it is being held:

    Message has a suspicious header

Either the message will get posted to the list, or you will receive
notification of the moderator's decision.  If you would like to cancel
this posting, please visit the following URL:

I have had these in the past. What is causing this response?