Hello @bhb1991
SPF alignment required the domain actually used for sending the emails (the mail-from) the match the domain the email appears to be sent from (the friendly-from, which for most customers is what they have connected as their email sending domain).
For HubSpot marketing emails, these will almost never actually match, as the mail-from domain will be hubspotemail.net. It’s only possible to achieve this kind of alignment with a dedicated IP and an additional add-on for a custom mail-from domain.
That said, this is typically not necessary for deliverability, and as long as customers have DKIM connected and HubSpot added to their SPF record, they should still be seeing their emails getting delivered.
For the contacts that are being quarantined, was this the first time emailing these customers?
Thank you!
Pam