Quarantined contacts and lists

HubSpot will quarantine contacts from an imported list or after a marketing email send if any of the following conditions are met:

• The list directly contributes to a high hard bounce rate (15% or higher) on multiple emails sent through HubSpot. For reference, a hard bounce rate of 1% is typically considered normal in the email industry. 
• The list contains email addresses with a known history of high hard bounce rates based on HubSpot's historical email data. These emails are also referred to as global bounces.
• Contacts were added through suspicious form activity. This scenario is most likely caused by a third-party with the intent of spamming the recipients' inboxes. 

How quarantined contacts and lists work

After contacts on a list have been quarantined, you won't be able to send marketing emails, including automated workflow emails, to those contacts. If those quarantined contacts are also present in other lists, they'll be dropped when sending to those lists.

The following contacts will be exempt from the quarantine: 

• Contacts who opened or clicked one of your marketing emails.
• Any contacts who opted in through a valid form submission.
• Contacts who reply to a one-to-one email sent from a connected inbox.

Please note: if you have the transactional email add-on, HubSpot will deliver a transactional email to a contact regardless of their quarantine status.

How can I see all the contacts in my account that have been quarantined?

If any of your imported contacts were quarantined, HubSpot will automatically create a list named Quarantined Contacts. To review this list:

• In your HubSpot account, navigate to Contacts > Lists.
• Search for and click the list titled Quarantined Contacts.

You can also create a list of quarantined contacts manually:

• In your HubSpot account, navigate to Contacts > Lists.
• In the top right, click Create list.
• In the right panel, enter a list name, then click Next.
• Add your list criteria:
  • Select Contact properties.
  • Search and select Email address quarantined, then select True.
  • Click Update filter.

• In the top right, click Save.

What should I do next? 

To remove individual contacts from a quarantined list:

• Send them a one-to-one email from a connected inbox.
• If a contact replies to a one-to-one email, they will be removed from the quarantined list.

Please note: the one-to-one email must be sent solely to the contact you're trying to remove from a quarantined list.

If your list is quarantined due to suspicious form activity:

• Enable CAPTCHA to verify that new form submissions are valid.
• Enable double opt-in to verify all new form submission as valid. This is a best practice for optimal email deliverability results.