Have you checked the ow_base_mail table to see if the emails are being loaded there for sending?
I am not 100% sure the core does this, if i remember wasnt there a admin notify plugin used for this... ill have to look....
(yes I tried a private message here)
Thanks!
read here (look at the post for july 18th, picture)
https://developers.oxwall.com/forum/topic/46645?&page=2
you can try here but he is not answering anyone, we feel he just walked away..
https://www.facebook.com/purusothamanr