I have set up a postfix which sends emails.
I have configure spf, dkim and dmarc (with p=none).
I have checked with mail-tester: spf and dkim work fine.
I have set up a dmarc rua in order to receive dmarc reports.
I have seen something strange in rua reports:
Sometimes SPF and DKIM are OK.
And sometimes DKIM fails (whereas SPF is good). My question is: How can this be possible ?
Thanks