Four causes: (1) No rua= tag in your DMARC record — check with: dig TXT _dmarc.yourdomain.com. (2) No email sent from your domain yet — receivers only report on traffic they’ve seen. (3) Your rua mailbox is rejecting the reports — test it manually. (4) You’re sending very low volume — some receivers only send reports if they’ve seen enough traffic from your domain. Google sends reports for any volume; Outlook has a minimum threshold.
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