@ModTeam
Can I point out that if you do start to have a significant users whose mail is instantly going to Spam - It might be worth having your email team reach out to Yahoo to see if there is anything they can do.
All email providers have a Postmaster address. In addition some have postmaster tools. These are used for the postmasters belonging to one domain to raise issues with the postmasters belongng to another.
As an example - When I set up my mail server, The Server was being blocked from sending Mails to Outlook.com addreses. I contacted the postmaster team at Microsoft in order to get the block lifted.
Similarly Yahoo have a page that your postmasters can use in order to contact them.
https://postmaster.yahooinc.com/
This also deals with delivery issues to AOL email addresses as well.
I must stress that this portal is NOT FOR END USERS. It is there for Email administrators of domains having issues sending.
I'm more than happy to provide the source code of mails from these affected users if you'd like.
Tim
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