Send undelivered sequence emails after being rate-limited
Because Mixmax sends your messages through your Gmail account, Mixmax is subject to any limitations set by Google, including rate-limiting for message sending. Google monitors the rate at which messages are sent through your account, not just the total number of messages you send in a 24-hour period. You can learn more about Google's specific account limits here. This means your account could be limited if you send a high volume of messages in a short period of time.
Mixmax has some safeguards in place to help prevent your account from getting rate limited. If you send your sequence to more than 500 recipients at once, we will space out your sending over multiple days — 500 messages per day — and space out the send times throughout the day. You can find some best practices on setting up sequences here.
Even with these precautions in place, there is still the possibility that the account will get rate-limited. If your account is rate-limited, we may be unable to send all of your sequence messages. If this happens, we will notify you via email, so you won't be left wondering. If you receive this email, you can re-try the undelivered messages.
How to retry undelivered messages
After your account is rate-limited, we recommend waiting 24 hours before retrying unsent messages, to make sure your high-volume sending doesn't raise a red flag again. To retry messages, go to the Reports tab for the affected sequence. The email you received includes a link to the sequence. Click the Resend to x recipients button — see screenshot below:
Your emails will be retried, and the send times will be spaced out, to minimize the chance of being rate-limited again.