HELP -- Activation Email Problem

[Calricdal]

Because of the recent invasion by spammers, we've set our forum to require email activation and verification.

The problem I'm having is that no activation email is being sent to the person who wants to register. I know this because I tested the feature by registering for my own forum with an email account that I rarely use. 5 days have gone by and I have received no activation email from my own forum.

I've had to go in an manually approve users who were waiting for activation emails that they never received.

So...What we do I need to do to make sure these activation emails are sent? I can't seem to find any settings in vBulletin options, or anywhere else for that matter, that I can tweak to resolve this issue.

We're using vBulletin 3.7.0 Thank you in advance for your help.