First check the Survey Invitation Log. If the survey was sent via Alerts & Notifications, first check the Notification Log depending how the survey was delivered. To check the Survey Invitation Log: 1) Click Survey Distribution Tools on the left menu, 2) Survey Invitation Log tab, 3) View past Invitations button, 4) try to find invitation in list based on the Invitation send time, Participant Email, Record ID, etc. You may need to 5) sort by date to get the most recent to appear or use other filter such as 6) Survey Record filter.
If the emails are showing as being sent in the Survey Invitation Log but the participants are not seeing them, please submit a ticket.