No Notification Email When a PM is Received?

[محروم.كوم]

One of my sites running 3.8.4 does not appear to be sending email out when a PM is received. I've tested it on two different usernames* both with "Send Notification Email When a Private Message is Received" set to yes and each of the accounts are under two different usergroups. Neither email address (one at yahoo.com and one at gmail.com) are receiving an email at all* not even in spam. I checked the mail queue on the server and do not see any emails still in queue.

Using Send Email to Users works fine. Using the Diagnostics > Email under Maintenance also works fine. I have ran Suspect File Versions as well and I see absolutely nothing suspicious.


Is there anything that I may have missed? I'm really not sure how long this has been a problem* but now that I'm aware of it* I would like to get it fixed if at all possible.

Thanks __DEFINE_LIKE_SHARE__