Gmail quirks
Gmail and it’s SPAM rating
It can be frustrating to find out that Gmail is delivering the emails you send to the spam folder. While we do everything we can to prevent this on our end by tightly controlling our network and what we allow to be sent over it, there’s only so much we can do before we have to pass this problem on to you. We can gladly share what we’ve learned here, and hope it helps you.
Do your best
You do your best by making sure you get the highest score out of 10 possible from mail-tester.com. It’s simple: go to mail-tester.com, copy the email address you were given, send the email to it, wait a few seconds, and then click the button to check your score. After that, do what you can to improve that score.
Report false positives in Gmail
Simply clicking “Not Spam” in Gmail can help a lot. Many of the filters are user-trained, and it’s entirely possible that at some point your recipients have done the opposite and reported your email as spam. This is not always “the” solution, but it can help.
Sign up for Postmaster Tools.
Google offers you a way to gain insight into your domain’s activity with Gmail. Take advantage of the opportunity that is presented to you: Get started with Postmaster Tools – Gmail Help (google.com)
Read the Google documentation
The best information you will get from Google is here, don’t skip a word of it: Prevent mail to Gmail users from being blocked or sent to spam – Gmail Help (google.com)