I have 2 organisations who are unable to send to or reply to my email address. Other users including myself can however quite happily send emails to and from this same account.
It is suggested that I should set up DMARC and DKIM for the domain. Whilst I can set up DMARC records in the DNS settings, how does one go about fully configuring DKIM on Treepl email host by way of entering the private key in a DKIM signer?