Most probably because your message did not pass the DMARC Authentication
To make sure go to
Then so clear error
Info about the DMARC
DMARC Records are published via DNS as a text(TXT) record. They will let receiving servers know what they should do with non-aligned email received from your domain.
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a mechanism for improving mail handling by mail-receiving organizations
According to the rfc7489
https://tools.ietf.org/html/rfc7489
Domain-based Message Authentication, Reporting, and Conformance
(DMARC) is a scalable mechanism by which a mail-originating
organization can express domain-level policies and preferences for
message validation, disposition, and reporting, that a mail-receiving
organization can use to improve mail handling.
What is DMARC Authentication? And how it passed the test ?
It is simply two things SPF and DKIM
To pass DMARC authentication, a message must both Pass and Align for either SPF
or DKIM. Even if a message passed authentication for both SPF and DKIM, it could still fail DMARC authentication if one of them does not “align.” There are two ways to pass DMARC authentication:
SPF and DKIM
How to set it up and solve it ?
It only takes a few minutes to get started with DMARC and you’ll see immediate benefits. The first thing you need to do is add a simple DNS record to enable DMARC reporting. If you would like MxToolBox to handle your DMARC reporting for you, just add this simple text (TXT) record to your domain’s DNS.
Ref:
MXTOOLBOX:
RFC:
