E-mail notifications not triggered to admin

I have a DW Question Answer plugin in my intranet WordPress.org page and it works fine, except for the e-mail notifications.
In the settings I already checked the “Enable notification” checkbox for new question, new answer and new comment, for both admin and followers, as well as the “Send a copy of every email to admin” checkbox in the main Email settings tab. I do get e-mails for new answers, but not for new questions or comments on existing answers. How can we check what is going on?
Regards,
Francisco