We have enforced a p=reject DMARC policy for one of our domains to counteract consistent spoofing attempts. This setup has historically ensured that all legitimate emails are successfully delivered.

Recently, we encountered an unexpected issue with our latest Mailchimp newsletter campaign, where 100% of the emails were blocked due to failing DKIM verification. This occurred despite having made no recent changes to our DNS settings, which are managed through Cloudflare.

We are currently investigating whether this could be related to a system outage at Intuit Mailchimp or perhaps an anomaly in the DMARC reporting process.

If anyone in my network has experienced similar issues or has insights to share, your feedback would be greatly appreciated!