[snakes1100]

Just move them to the reg'd group, your going to get it when requiring email verification, typically its caused by the ISP in question that the user is reg'ing with.

As from a vhost server you wont have mail log access, it would be hard to find out why the emails most likely failed to be delivered or they're ISP in question placed them in that users spam box, as a lot of users dont chk their spam box, it becomes a issue as the forums cron sends those reminder emails out daily.

If it's mainly free email services that are failing, make a reg page change and notify reg'ing members that hotmail and the like are not permitted to join your forum.