This could be due to a number of reasons:
Double-check that you have specified your email address in your DMARC record and that it is correctly formatted. For example: rua=mailto:[email protected]
Check if you have specified any size restriction in your DMARC record in respect to the aggregate reports. For example: rua=mailto:[email protected]!10m. You may want to remove the size restriction as some URI parsers may incorrectly parse the “!” in the URI.
Typically reports are sent within the first 24 hours of adding the DMARC record.
If your email volume is very low it may take extra time for the first report to arrive.
Your anti-spam filter may be blocking large files of type ZIP.