There might be a 1-hour delay. The campaign starts working about once every hour when it starts pulling the list of contacts that should receive the survey and sends the survey based on the schedule. Depending on when exactly in between this hour you have switched the campaign ON, it may take from a few minutes to up to 1 hour for the surveys to be sent out.

Contacts do not match the schedule. If you've switched OFF the campaign's recurring schedule and only want to send the first survey, then please keep in mind that the "First survey" rule targets only new contacts that have never before been surveyed via Retently. If a contact has already received a survey before, then they no longer match the "First survey" schedule rule, and since the recurring schedule is switched OFF, this basically means that the contact will never be surveyed in this campaign again. If you still need to survey your contacts based on the first survey rule and keep the recurring option OFF, then consider either sending the survey manually or resetting the last survey date of your contacts, so that our system would consider them as new contacts.

The contact no longer matches the campaign's time frame or day of the week. You can check these settings in the campaign's Schedule section. Also, please make sure that the configured time frame gives the campaign at least 2 hours to ensure that surveys will be sent on the same date that the campaign was switched ON.