The 2 most common problems are:
1. Spam blocked
2. Mistyped email address.

To find out if either of these is the case for you. Simply try logging into your account. You will either get a message saying: 
1. This account has not been activated
2. This is not a valid account

1. White list or “approve” as a valid email in your spam block program. Then push the button to resend activation email (on message 1 above)
2. Register with a valid email account that you wish to use for your 5Degrees login.