I am attempting to allow mailchimp to set the from email on my campaigns to an account that I setup on my mailinabox server for my company. I have added the DKIM CNAME record and the SPF text record, however, when a user requests to sign up from my website, the confirmation email goes to spam, stating that:
It has a from address in my.domain but has failed my.domain’s required tests for authentication.
I have tried adding postfix options, but nothing seems to work. Messages still go to spam. How can I allow mailchimp to send out emails using a specific user in MiaB?