Some New Users Are not getting Registration Confirmation emails.

Hello,
I have opened my website up to a small group of people to help me put it through its paces to make sure everything is working correctly. One thing that seems odd is that some of the people who register will recieve a confirmation email but others are not getting them.

I have already done the “check your spam/junk folder route”. No firewalls or anything like that … These are people who I have used for testers for many years with other platforms.

How can I best fix this situation to make sure everyone who registers gets a confirmation email?

Thanks
gary