Forum Discussion
Microsoft's e-mailservers break DKIM on non-ascii characters
There seems to be some kind of character encoding issue in DKIM signatures applied by Office365 servers. We just had a DKIM fail ('body hash did not verify') and tracked it down to non-ascii quotes b...
I am not convinced about the part that it is explicitly microsoft who breaks dkim... but your point on the character encoding gave me an idea... my issue is that messages from one mailing system get dkim=pass in gmail, but dkim=fail in outlook (body hash fail).
I decided to check and compare html source.. and found that gmail shows encoding utf-8 in html header, while outlook shows encoding iso-8859-1. bodies with different encodings would result in different hash, of course. I am investigating if the email generating system specifies encoding before sending. If it is not specifying encoding, I will check if specifying it solves the issue.