When I send my newsletter to people, it ends up in the PROMOTIONS folder on gmail. I know I can have them whitelist the sender but for a 70-80 year old person this is like rocket science *AND* they may never see the instructions on how to do it.
How can I get my email to not go into that folder? Is it a header or something that is causing it?
I tested from the newsletter email address directly. I did this from the pop3 account and it went through fine. So it is detecting something to do with the email formatted by your plugin. Perhaps the return path, perhaps something in an X- header? I don’t know either but it is definitely only mail sent from your plugin and this is a problem.