To make sure your previous subscribers in HubSpot can resubscribe to your emails through Sleeknote, you need to turn on the “Resubscription email” option in your HubSpot account.
Here's how you can do that.
1. Log in to your HubSpot account and click the Settings icon in the top right corner.
2. Find the "Tools" section on the left-hand menu. Expand the "Marketing" option and click "Email".
3. Click "Subscriptions" in the top menu and turn on the “Resubscription email” option to allow unsubscribed people to subscribe again.