Spam Check VS Unspam.email

You should check to see if the messages that are being sent contain any links that would be considered questionable/spammy. You can also try taking the content of one of the messages and checking it’s spam assassin score ( https://spamcheck.postmarkapp.com ). Source: about 2 years ago

Build a clean email that passes a spam check with flying colors (https://spamcheck.postmarkapp.com/) then use a warmup service like lemwarm, inboxally or neverspam as mentioned in the other comments. Source: over 2 years ago

The issue sounds more email centric. You're likely hitting the Apache SpamAssassin limit on the remote email servers. Use https://spamcheck.postmarkapp.com/ to check the score of emails you've had declared spam, and follow recommendations to improve. Source: almost 3 years ago

Also, send email messages from your domain to https://unspam.email/ and https://www.mail-tester.com/ for analysis of deliverability issues. Source: over 1 year ago

Use deliverability tools like https://unspam.email/ for more analysis. At least, you'll be able to see via the headers whether everything is configured correctly. Is the WP site hosted on a VPS or do you have the ability to look at the config files / logs on the host ? Source: almost 2 years ago

Getting a bunch of warnings from https://unspam.email/ that I cannot seem to figure out how to clear up, they are the following list. I will gladly pay $15 for someone to help me get these issues resolved (without creating more issues), I have full control over the DNS. Source: over 2 years ago

Unspam is currently available for 30% off with the code “BLACK” until November 30. - Source: dev.to / over 2 years ago

Try services like https://unspam.email/, and it will scan your reputation and deliverability. With the output feedback, you can work and decide what works badly. Source: almost 3 years ago