Inactive Users by Default (Urgent)

Hi. Please see the attached screenshot. This is from the list of "All Members" in Membership plugin.

When people are signing up as Registered Users (the free level) they are receiving the confirmation email but unable to login to the site. When I looked in the All members list, it shows (as you can see in the screenshot) that they are inactive, even though they have just signed up (and have nothing to pay).

This site is live now, hope someone can help ASAP.

Thanks for your time. Andrew.