[imp] Messages from Horde/Imp are in many cases marked as Spam

[Administrator Chat-Net]

Hi all

When I'm sending messages to other users from my Horde/Imp, It's in  
many cases marked as
Spam.
Does anyone know why this could be?
The Spamassassin Headers are the following:

X-Spam-Flag:  YES
X-Spam-Level:  ******
X-Spam-Status:  Yes, hits=6.0 tagged_above=-1000.0 required=4.0  
tests=AWL, BAYES_50,
HELO_DYNAMIC_HCC, HELO_DYNAMIC_IPADDR2, RCVD_IN_NJABL_DUL
-- 
Administrator Chat-Net
Projektleitung und Administration
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