The purpose of the status column inside of any given contact list in Autopilot is to let you know if an email address you've entered is valid or invalid. Usually if a contact is displaying as invalid, it's because the email address you've entered for them has been misspelled. It could also mean that their mail server is blocking your emails or that the recipient's mailbox is over quota. If you see an email address which is unverified - that simply means that you've yet to send anything to this contact so Autopilot does not know if it will go through or not. After a message is sent which goes to that contact, the status column will update for that contact.
If you'd like Autopilot to check to see if an invalid contact is now available to receive emails, you can check the box beside that contact and click "Validate" across the top bar above the list. This will simply ping the mail server of that recipient to find out if that mailbox is available to receive mail. It will NOT send them an email to perform this check. If the mailbox is available - the status will change from invalid to valid.