“No DMARC reports received in last 7 days which confirm DKIM signing
Sign using DKIM and send email to a DMARC receiver”

What do I need to do?

If the domain is supposed to send mail, and you do get dmarc reports (Volume > 0), then you should make sure that the sending servers/services are configured to correctly DKIM sign mail for your domain.

If the domain is not supposed to send mail, you should make sure that no servers are allowed in SPF (“v=spf1 -all”), and that the domain is placed in a dmarcian group for inactive domains.