Why is email from my WordPress site going to spam.

The quick answer is, there is no quick answer. But there is a quick way to find out.

  1. Install or activate the "WP Mail Logging" plugin.

  2. Go to https://www.mail-tester.com/

  3. Now register a new user to that email address. Usually I just call it "spam tester".

That should generate a new user email to the test address.

Now on the mail tester site, you will get a full report on the deliverability of the site generated email.