On 7 Nov 2018, at 19:12, Jasen Betts via Exim-users <exim-users@???> wrote: > DKIM signing is done after the transport filter. (and headers_add etc)
> this is not the problem.
I concur; I just tested this with a simple transport filter and sent a message to a Google Mail account, in which the DKIM headers pass validation without error.
To the OP: you’ll most likely need to run in debug mode to see what/where is mangling your message. It would also be useful and instructive if you let us know your OS and Exim versions.
