Pending message for registered user

Hello,

i'm registered at nabble forums and subscribed to servicemix user mailinglist. Although my message (http://www.nabble.com/X509-Signature-for-Client-tt16761353.html) has a pending status even if i try to resend the message. I only get an email whith this information:

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

 users@servicemix.apache.org
 SMTP error from remote mail server after end of data:
 host mx1.eu.apache.org [192.87.106.230]: 552 spam score (5.4) exceeded threshold

What is the problem? I need urgently help from servicemix forum!!!

Greetings,
Andrea