After upgrading to 16.0.1-017 I experience the issue described, sort of....
I may read it wrong or misunderstand something, but as I read it it should only happen if the body is empty. Or am I wrong here?
Conditions:
An empty body message canonicalized in 'relaxed' mode. The body hash calculated for an empty body and 'relaxed' mode gives the same value as in 'simple' mode. The value is 'frcCV1k9oG9oKj3dpUqdJg1PxRT2RSN/XKdLCPjaYaY='
I did some tests and they showed that I had to have a quiet big chunk of text in the message body to get a Pass on DKIM and had to put in at least around 100 words before it got a pass.
The suggested work around, change the Body Canonicalization to simple works fine, but I still would like to know if I interpreted the https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvh84754 article all wrong or if the text may need some adjusting.
Michael