Our business sends construction work orders via email to contractors using our proprietary email generator through a Securence (US Internet) email system. The sender address reflects our client's email address, not ours. It is designed to deliver from any email address to any email address. It has failed to deliver except when the sender has a yahoo email address, in which case it will deliver to all addresses we tested except recipients with yahoo or gmail accounts. No other sender email addresses have caused this problem. Any suggestions? Is this a DMARC thing? Special SMTP or POP settings needed?
... View more