I just registered after using the site for some time and my registration email from email@example.com got marked as spam by my mail server. I have somewhat aggressive settings, but it looks like there's something going on with either the OpenDKIM DNS TXT record or the actual key. My logs are below:
opendkim: A037FE1605: not authenticated
opendkim: A037FE1605: bad signature data
postfix/qmgr: A037FE1605: from="firstname.lastname@example.org"
Here is the relevant header info from the message
<br><br>Authentication-Results: dkim=fail reason="signature verification failed" (1024-bit key) header.d=serverfault.com email@example.com header.b=J2pWFCFJ DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=serverfault.com; s=dk; h=Content-Type:Message-ID:Date:Subject:Reply-To:To:From:MIME-Version; <br> Received: from [10.7.2.15] (helo=[169.254.0.2]) by mx-out.stackexchange.com with esmtp (Exim 4.72) (envelope-from <firstname.lastname@example.org>) id 1Z31fJ-0007sr-TN; Thu, 11 Jun 2015 12:33:01 +0000 –