When I send a message using an external SMTP client, DKIM signauteres on messages will not successfully validate.

When I use the built in Zimbra webmail client they validate successfully every time.

Both tests use the same email address, username/password etc. The only difference is the client used to send the mail.

I used this guide: Configuring for DKIM Signing - Zimbra :: Wiki to configure DKIM without any issues other than the one noted above.

$zmcontrol -v
Release 8.0.0.GA.5434.UBUNTU10.64 UBUNTU10_64 FOSS edition.

To test DKIM, I used the port25.com service. Upon emailing check-auth@verifier.port25.com, here are the relevent results I recieved for both the Webmail send, and the SMTP send.

SMTP Test:
Result: fail (wrong body hash: expected RzsU67ywQxiXDb1FZkrH7WnlatX9SyWIGQ8D3jY6geA=)

Webmail Test:
Result: pass (matches From: notifications@removed.com)

I get the same results using Gmail's "mailed-by:" and "signed-by:" headers. Messages send using the Zimbra Webmail client are 'signed' whereas messages sent using a SMTP are also signed, but do not validate.

What other pertanent information can I supply to help?