Tips when sending to Yahoo! Mail ends up as spam

This is Haraoka from Beyond.

I'm having a bit of trouble, so I'd like to make a note of what to do when an email sent to Yahoo! Mail ends up as spam.
When I sent an email to a customer from a certain content, I didn't receive a reply, so I checked and found out that it seemed to have gone into my spam folder.

DNSBL check

First, check the DNS blacklist.
http://www.dnsbl.info/dnsbl-database-check.php

Open relay server check

Check to see if it is being relayed to a third party (stepping stone)
http://www.rbl.jp/svcheck.php

Check SPF record

Make sure your DNS SPF records are properly configured.
http://mxtoolbox.com/spf.aspx

Yahoo! Mail blacklist removal request

This time, there seemed to be no problems with any of the checks ① to ③. When I looked closely at the header, X-YahooFilteredBulk ", so I checked and it seems like I was caught on Yahoo! Mail's blacklist.

It's a mystery as to why it was flagged as the content was not sent much, but if you ask Yahoo Mail's customer service to remove the blacklist, they will take care of it.

http://ms.yahoo.co.jp/bin/mail-ms/feedback

*A confirmation will be displayed first, so you can make inquiries from the page that changes by clicking "Next".

This time, I received the email safely within 30 minutes after making the request.

So for your reference.