There are daily send limits for both one-to-one emails and sequences emails sent from your connected email accounts in HubSpot. HubSpot will alert you when you're close to hitting either send limit. These limits apply to a rolling 24-hour period and do not reset at a specific time of day.
A daily send limit on automated emails sent via sequences. This includes any sequences emails that are scheduled to send from previous or new sequence enrollments and paused sequence enrollments. Your send limit varies depending on your HubSpot subscription.
Email provider limits
Each email provider has its own rate limits on the number of emails you can send each day. Limits for inboxes connected with Exchange or IMAP vary depending on your mail client; learn more about rate limits for Gmail and Office 365.
A provider's rate limit sometimes include additional limits, such as a bandwidth limit. Therefore, it's possible that you could reach your provider's limit even if you haven't exceeded the number of allotted email sends.
Please note: connecting the same Office 365 account multiple times to a HubSpot account can cause you to quickly hit the rate limit error. It is recommended to connect the Office 365 email address to a single user's account.
There is a daily send limit on one-to-one emails sent from a connected inbox. This daily send limit applies to emails sent from a personal inbox or a team inbox. These limits prevent you from exceeding your email provider's send rate limit. HubSpot send limits vary based on each email provider's limit:
Gmail Free: 350 emails per day
Google Apps: 1000 emails per day
Office 365: 1000 emails per day
Exchange inbox: 1000 emails per day
Generic inbox: 1000 emails per day
Additionally, if you connected a hosted inbox to your conversations inbox, the send limit for your hosted inbox depends on your HubSpot subscription:
Free HubSpot account: 500 emails per day
Paid HubSpot account: 5000 emails per day
Due to limitations in Microsoft's Graph API, each email sent from a connected Microsoft Outlook inbox is subject to a maximum size limit of 4 MB. To avoid exceeding this limit, you can reduce the size of your emails by trimming out extraneous   characters in the body of your emails, and minimize the number of emails in a single thread.
The sequences send limit is based on the number of sequences email sends on a given day, not the number of new enrollments. The limit includes all emails sent immediately when a contact is newly enrolled in a sequence and any scheduled sends from previous enrollments. For example, if your sequences daily send limit is 500 and you already have 450 emails scheduled to send on a given day, you can only schedule an additional 50 sequences email sends that day.
HubSpot will notify you if you try to start a sequence with emails to send on a day when the limit has been reached.
If you're close to your daily limit, you will see a yellow error message in the bottom right corner telling you how many sequence emails you have left to send that day.
If you see a red error message in the bottom right, you have hit your send limit. To see which email you need to update, select All contacts from the left panel. The email step will be listed at the top. Navigate to the email step, then use the dropdown menus to update the date of the send.