When some contacts don't get a HubSpot marketing email, HubSpot usually never sent it to them. It leaves out contacts who unsubscribed, hard bounced, reported spam, are set as non-marketing or count as unengaged, to protect your sending reputation. That's why the Sent number on a campaign can be lower than the segment you picked.
The first check takes a minute. Open the sent email, go to the Recipients tab and click Not sent. The Filter by dropdown sorts those contacts by reason: Previously unsubscribed, Previously hard bounced, Previously marked as spam, Unengaged, Reached frequency cap and Other. If the contact shows under Delivered, their mail server accepted the email, and the problem is spam filtering or quarantine. That's covered in HubSpot emails going to spam.
Why contacts don't receive HubSpot marketing emails
They unsubscribed, or never opted in
Every marketing email has a subscription type. A contact who unsubscribed from that type, or from all email, won't be sent it. On the contact record, click View subscriptions in the Communication subscriptions section to see Subscribed, Unsubscribed or Not specified for each type. With data privacy settings on, Not specified isn't enough, because HubSpot expects explicit consent. If Limit emails to contacts with a subscription is also on, only opted-in contacts with a legal basis are emailed. Forms with double opt-in add one more case, where the contact never clicked the confirmation link.
They're non-marketing contacts
In paid Marketing Hub accounts, only marketing contacts can receive marketing emails. That includes form follow-up emails and Send email actions in workflows. Non-marketing contacts are grouped under the Other reason. Check the Marketing contact status property on the contact, then Marketing contact until next update. If that one says Yes, the contact is marketing today but switches to non-marketing on the next update date. The Marketing contact status source type and source name properties show which tool or user made the change. The marketing contacts limit guide covers setting contacts as non-marketing.
They bounced or reported spam before
Contacts who hard bounced in your account are left out of later marketing emails, and so are global bounces, which are addresses that hard bounced in three or more HubSpot accounts. Contacts who reported an earlier email as spam are left out too. HubSpot also refuses addresses that fail validation, which can include role-based addresses like sales@, and known disposable domains. The Email hard bounce reason property shows why a contact bounced. See hard and soft bounces in HubSpot for when you can unbounce someone.
HubSpot treated them as unengaged
The Don't send to unengaged contacts setting is on by default. It skips contacts who have never engaged and ignored your last 11 marketing emails, and contacts who engaged before but ignored the last 16. Opens and clicks both count as engagement, tracked in the Sends since last engagement property. These contacts appear under the Unengaged reason.
Your recipient settings left them out
Check the Send to and Don't send to selections on the email. A contact in a Don't send to segment is excluded unless you also added them to Send to as an individual contact. If you use a send frequency cap, contacts who already got the maximum number of emails for the period show as Reached frequency cap. As of October 2026, the frequency cap needs Marketing Hub Enterprise, according to HubSpot's frequency safeguard article. Contacts with no email address don't appear under Not sent at all, so they're easy to miss.
How to fix it
- On the email's Recipients tab, click Not sent and filter by each reason in turn. Use the Actions menu to save each group as a segment.
- Leave unsubscribed and spam-reported contacts out. HubSpot won't email a contact whose status for that subscription type is Unsubscribed. Only change it when the person asks, for example through your subscription preferences page or a form with a consent notice for that type.
- For non-marketing contacts who have opted in and should get marketing email, set them as marketing contacts. They will then count toward your marketing contact tier and your bill.
- For unengaged contacts you still want to reach, clone the email, turn off Don't send to unengaged contacts in the clone, and send it to that segment.
- For frequency cap drops, clone the email, clear Apply send frequency cap for this send, and send the clone to that segment.
- For bounced contacts, fix the address or unbounce it first, then clone and resend. HubSpot doesn't resend dropped emails by itself.
How to stop it happening again
Before you send, open the Audience section in the email's send settings and click Review reasons. HubSpot shows how many of the selected contacts won't get the email and why, with a View in segments link and recommended actions for each group. Pick the subscription type that matches the content, and check the default marketing contact status for your forms and integrations so new contacts land with the status you intend.
From client work
For Kingstown College, I imported more than 20,000 student and prospect records from Full Fabric as non-marketing contacts, with 1,734 unsubscribes opted out of all email. Marketing status follows the consent field from Full Fabric, so nobody is emailed without opt-in. In a portal set up like that, a contact without opt-in showing under Not sent is the intended result. Read the Kingstown College case study.
If a whole segment keeps getting skipped and you can't see why, book a free 30-minute call and I'll go through the send with you.
Questions
Why is the Sent count lower than the number of contacts I selected?
HubSpot removes contacts who unsubscribed, bounced, reported spam, are non-marketing or are unengaged before it sends. HubSpot's graymail article notes that skipping unengaged contacts alone can make the sent number lower than the Send to count.
Can non-marketing contacts still get emails from my team?
Yes. HubSpot lets you send one-to-one sales emails, sequences, registration emails, ticket kickback emails, transactional emails and feedback surveys to contacts whatever their marketing status.
Will dropped contacts get the email once I fix the reason?
No. A marketing email that was dropped isn't sent again. Clone it and send the clone to a segment of the contacts you fixed.
Did this fix it?
Good to hear. If something else in the portal looks off, the help centre has more fixes.
Some problems need someone to look inside the portal. Book a free 30-minute call and show me what's happening. If it needs work, you get a written scope and one fixed price.