In which case that's now two emails that your mail server has eaten. Please check firstly that the Email address in your profile is accurate, then if it is, use the webmail for your account and check the provider's spam or bulk mail folders.
The registration activation emails are prioritised by the forum software and are sent immediately, I'm not saying that it is completely infallible, but the fact that two have now gone missing, points to a problem at your end.
I have just now sent a third one.