A list can be quarantined upon import or when you attempt to send a marketing email to the contacts on it if any of the following conditions are met:
- The list directly contributed 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 emails 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.
Once the contacts on a list have been quarantined, you will not be able to send marketing emails, including automated workflow emails, to those contacts. If those quarantined contacts are also present in other lists, they will be dropped when sending to those lists.
Contacts on quarantined lists who have opened or clicked one of your emails will be exempt from the quarantine. If your list was quarantined due to a high rate of hard bounces or known global bounces, any contacts on those lists who opted in through a valid form submission will also be exempt. You can continue sending to these eligible contacts.
What should I do next?
High hard bounce rates indicate an issue with the health of a list. This could mean that you have sent emails to lists with outdated email addresses, contacts from a purchased list, or received an inordinate amount of spam complaints on your emails over time. This is a good opportunity to evaluate your methods for collecting contacts and lists. Learn more about best practices for managing your contact lists.
If your list is quarantined due to suspicious form activity, you can enable CAPTCHA to verify that new form submissions are valid. Enabling double opt-in will also verify a new form submission as valid, and is a best practice for optimal email deliverability results.
How can I see all the contacts in my account that have been quarantined?
- In your HubSpot Marketing Hub Basic, Professional, or Enterprise account, navigate to Contacts > Lists.
- Search for and click the list titled Quarantined Contacts.
If you are able to verify that some of your quarantined contacts have valid email addresses and you've successfully reached out to them outside of HubSpot, contact HubSpot Support.