Your sequence email step fails with the error message: Send failure - please ensure send and sync are enabled in mailbox settings.
Navigate to your mailbox settings by clicking on your initials in the lower left-hand corner of the screen, click the Mailboxes tab, and click Edit next to the appropriate mailbox. Ensure that the send and sync settings are green (enabled). If they are grey, click the icons to turn them green.
This issue occurs when the send and sync options on your mailbox become disabled. This may be due to a manual action on your part or an admin's, or we may have temporarily lost connection.