I've started getting notifications that gmail and some other sites are now rejecting emails sent out by the forum because this site had passed some failures threshold they have.
2 things seem to have happened lately.
The first was gmail added the forum to a spam list.
The second was a huge increase in spammer activity. This has probably resulted in the failure threshold being crossed, since the majority of the registration attempts never get their emails for various reasons, and thus never go live.
Just now though normal emails being sent out for thread posts just got rejected.
So just be aware that some sites are not passing your forum mail along to you.
Domain writersanctum.com has exceeded the max defers and failures per hour (5/5 (100%)) allowed. Message discarded.