If the setting is set to send the survey when the status of a ticket is changed to Resolved or Closed, the satisfaction survey would be sent along with the Requester notifications of 'Agent Solves the Ticket' and 'Agent Closes the Ticket' respectively.

Please navigate to Admin > Workflows > Email notifications > Requester notifications and toggle on the corresponding email notification to make sure that the survey is sent. If this is toggled off, then the survey would not be sent.

The survey will also not be sent on tickets where the requester of the ticket is also an agent on the helpdesk as it is not considered ideal for an agent to rate another agent.