Contacts not receiving campaign emails when "unengaged non marketable" status

Hi, anyone know why emails in campaign are not sent?

You have the answer in your subject line. They are listed as non-marketable. This has happened because there has been no response or activity from them directly for a significant period of timeā€¦ie, they are very cold leads.

https://help.infusionsoft.com/userguides/contact-management/create-and-manage-contacts/email-status-icons-explained

Non-Marketable: The Non-Marketable email status is assigned to email addresses during import or when a person is added manually, but you did not indicate that you have permission to send email marketing to them. Click on Manage Email Status to manually update the email status for a specific email address. You can send individual emails to Non-Marketable email addresses, but cannot send any broadcast or follow-up sequence messages to them.