TOPIC: Emails not being sent out

I am using 2.7.3a and Im have registered of a thousand people over the past two weeks for a number of events. The big problem that I am experiencing is that the system doesn't seem to send out all the confirmation emails to the registrants.

I have triple checked my event settings and the Custom Thank You letter is set to YES and most of the people are getting them but I would day 30% are not.

I have them check their spam and junk folders but it looks like the emails are not getting sent out. Is there a way I can see if DT Register sent an email out or not? I need to determine the source of this problem.


Thanks

Jason