[BlueOnyx:26735] Re: DKIM

[Michael Stauber]

Hi Richard,

> v=DKIM1; k=rsa; 
> p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDGZqcsl8kAZREYi+KatsmFL35XTGYZuAEO3baCGHSXFZ+DzpHs3SNtczldMFCZybgU/n+hlXQlE1Pca0wiiPkbYIxd813CRhh+URkuPLZcQGFeJK08v4OBS3j6SnjaYq/2evvbe4b8NuwqfSV8lzwcsFP39yJZVngi0em2fuD5VQIDAQAB
 >
 > 
https://mxtoolbox.com/Public/Tools/EmailHeaders.aspx?huid=2cd2b490-c533-4f46-9135-10335cf9ff51

The error message from MX-Toolbox is:

DKIM Signature Body Hash Verified 	Body Hash Did Not Verify

The DKIM stuff seems to be properly set up on your server and when I 
check the validity of the DKIM it actually looks good.

The most common reason for this error is that the email content (the 
body) was altered after the DKIM signature was applied. DKIM signatures 
are very sensitive to changes in the email. Even a minor alteration like 
changing a character or adding a space can cause the body hash to not 
verify. This could happen due to forwarding, auto-responders, or any 
intermediate servers that might modify the email content.

Sometimes, during the transit of the email from the sender to the 
recipient, the email might go through various systems or services that 
could alter its content or format. This includes MTAs (Mail Transfer 
Agents) or email gateways that might modify the email, causing the DKIM 
signature to not match.

Ensure that the email is not being altered in transit. If the email goes 
through any intermediate systems, check to see if they are modifying the 
email content.

Try sending a very simple email (with minimal formatting and content) to 
see if the issue persists. This can help determine if the problem is 
with the email content or with the DKIM setup itself.

For example:

Your Email also has ARC related headers. If these were applied AFTER the 
email has been signed by DKIM, then that might cause this issue. You'd 
usually first apply ARC headers and then let the email be signed by DKIM.

It could also be that in the process of forwarding and/or SPAM-Filtering 
changes were made to the message body. Like when the forwarder (if it 
wasn't a BlueOnyx forwarder for example) added a custom footer to the 
email body.

-- 
With best regards

Michael Stauber