Why are DMARC failure (forensic) reports not supported by major ISPs such as Google, Microsoft, Yahoo, etc.?

DMARC failure (forensic) reports are not supported by major ISPs such as Google and Microsoft because these reports contain Personally Identifiable Information (PII). Specifically, these reports include details like the "From" address, "To" address, subject line, and the email header. Sharing this level of detailed information raises privacy concerns and potential legal issues, leading ISPs to avoid supporting forensic reports to protect user privacy.

The good news is that one of the major ISPs, Yahoo, has started generating and sending DMARC failure reports. Previously, Yahoo only sent DMARC aggregate reports.
Now, with these new failure reports, you can view detailed information in your Failure Reports section and use them for more precise troubleshooting and analysis.

For step-by-step guidance, see our article: How to Analyze DMARC Failure Reports.