Please follow these steps to remove a contact from Global Unsubscribe list so that he can get emails.
1. Hover your cursor to the account name (on the top right) and click on Account Settings.
2. It would divert you to the details page where you will find "Do Not Mail List". Kindly click on Manage.
3. Here search for an email address which you want to remove from DNM list with the help of the Search bar.
4. Now please click on Delete from the Actions on the right-hand side. The contact will successfully remove from the Global Unsubscribe list.
NOTE: - If the user is unable to see the Manage link on the Account Setting's page then he needs to consult the Admin of the account for the necessary privileges to view the link.