> I just keep getting a message telling me my message
> was rejected for policy reasons. It would be helpful
> to know what policy my message contravenes so I can
> edit it to remove the contravention! 

I frequency get that.
Cause #1, including html in the reply 
I use angle/space/a href="..." or angle/space img="..." the space invalidates
the code.

Cause #2, A reply being open too long or two replies being opened.
Back space, select all and copy. Cancel and start a new reply, paste.