Please note: contacts who have opted out of your marketing emails can take action to resubscribe to your emails or update their email preferences. This includes contacts who have unsubscribed from marketing emails sent from your HubSpot account, and contacts whose opt-out status was manually changed by a HubSpot user.
In your HubSpot account, navigate to Contacts > Contacts.
Select the checkboxes next to the records you want to edit.
Click the More dropdown menu, then select Edit communication subscription for contact.
In the Communication subscriptionpanel, select the Remove opt out from all email checkbox.