One of the most important marketing tools in an author's toolbox is their mailing list; it's old-school, but it works. However, with the enormous quantity of malicious spam flying around the internet, mail companies are constantly building new layers of defense which authors must successfully navigate lest they fall foul of spam filters. Like I have.
UPDATE at the end — it's working!
If you're a subscriber of my newsletter, please check your spam folder. It would be a huge help if you marked any of my emails there as "not spam". You can also add my newsletter email address to your contacts to white-list it.