If you did not receive an email with confirmation, the first thing you should do is check if the email address you entered is correct, if this is not the problem, try to send a confirmation request, maybe there was a technical problem at the first attempt.

In the other case, check your spam folder in your inbox, or contact the support team of the site you sent a confirmation request to, and find out what could go wrong. If none of the actions above, did not help, check the security settings in your mail service, maybe letters from the site are blocked automatically. In any case if you have not received the letter within 5 minutes try to use another mail for confirmation or try again later.