Pro Site Activation Link Not Working

1- Is there someone that details setup on Pro Site. I have looked at the related blog posts and such.

2- Specifically, as the administrator I am receiving an email with an activation link that does not work. But the user is receiving no such email. Am I supposed to activate it for them (though activation link is not working) or should they be receiving an email themselves to activate themselves. Because I am doing this for the first time, I am not sure exactly what the default process looks like.

Here is the activation link:

Thanks in advance for your help.