I have searched the documentation related to email deliver but have not found anything related to the specific issue that I am having.
1) Test emails from the plugin are working and are being delivered.
2) Test newsletters are being delivered without issue.
3) All other wordpress site emails are working correctly.
4) I have enabled double opt in for new subscribers to subscribers. The confirmation emails to new subscribers are not going out. When I go to resend them from the manage subscribers screen, it indicates that the email is sent, but it is not delivered.
Only the subscriber confirms are not being sent.
Any ideas on what could be causing this?
Thanks.