No, SpamAssassin isn't blocking it. Something else is, but saying
"SpamAssassin".

SpamAssassin doesn't have the capability to block messages.

At 01:58 PM 3/19/2008, dougp23 wrote:

>I am seeing a strange problem. A woman at our company sends out a
>newsletter, and several people said when they replied, the reply was
>rejected on our end by SA. A little testing shows this is true!! If you
>compose a message from Yahoo to Julie, it goes fine. If she sends one to
>your Yahoo account and you reply, we reject it, even though it scores a -1.3
>
>I'm stumped!! Here's some headers from our most recent test:
>
>I changed server names and IPs around a bit, but I kept it consistent. Any
>help would be great!!