Domain-based Message Authentication, Reporting, and Conformance (DMARC) aggregate reports are usually generated once a day. However, you can request more frequent reports by configuring your DMARC record with the ri tag with a shorter time interval. Shorter time intervals are honored by supporting mailbox providers on a best effort basis.
If you are waiting for your first aggregate report, please allow at least 24 hours after you publish a DMARC record in the Domain Name System (DNS) to receive it.
Forensic reports are intended to be delivered by mailbox providers almost immediately after detecting a DMARC authentication failure. However, due to potential privacy and performance concerns, most mailbox providers do not send them.
For additional information on DMARC tags, go here.