I have spent hours narrowing this down to a thunderbird problem
Long story short:
We get emails from a contact form on our website, I reply to them.
The emails contain html. Using thunderbird to reply will cause the dkim to fail according to google:
They also fail DKIM at mail-tester.com and dkimvalidator.comdkim=neutral (body hash did not verify)
Searching this forum, this error seems to get blamed on the mail server.
But, I have tried 2 other mail clients, Apple mail on OSX and mymail on IOS
Same server, same email message and it passes DKIM with both clients
Now the interesting thing:
Thunderbird will send the message in the 7 bit format:
Code: Select all
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
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Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
charset=us-ascii
Code: Select all
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: base64
And also that thunderbird chooses this encoding based on what the smtp server says it accepts.
Now if I send a pain text message using thunderbird, the email will pass DKIM
So I am pretty sure having html in the message causes this, I have not narrowed it down to what specific html in the message causes this.
Does anybody have any guidance on this?
I dont want to stop using thunderbird, there must be a work around..that I have not figured out.
Also: Im On the TB beta channel so using 88.0B2 at the moment