In accordance with advancing internet standards on email authentication, new authorized sending domains added to your DuoCircle Outbound SMTP account starting December 13th, 2025 will require a valid DMARC record. 

NOTE: this change is not retroactive; domains successfully validated prior to 2025-12-13 may continue to send.  We do, however, very strongly encourage adopting DMARC as it is rapidly becoming a hard requirement for mail acceptance at many mailbox providers. 

Use our DMARCReport service for easy-to-use DMARC report collection and analysis to simplify your DMARC monitoring and protect against email spoofing → DMARCReport.com

For domains detected as not having a suitable minimum DMARC record, guidance is provided via the Sending Domains tool in the client area for configuring a minimal DMARC record: