Our email domain is hosted through Exchange Online (Office 365). Customers email
support@ourdomain.xyz which is delivered to Exchange. Exchange rewrites the TO email header to the email address associated with our Zoho Desk (
support@ourdomain.zoho.xyz). Most of these messages get delivered to desk successfully, but I'm seeing an increasing number of emails being hard bounced with an SMTP 5.7.1/DMARC error similar to the one below.