If you logged in after the time allotted by the lecturer for attendance tracking, this is not a malfunction of the app. For attendance tracking, you must be present at the time of tracking.
If you have recently enrolled in the degree programme after the lectures began, your matricola may not yet be registered. Ask the faculty member requesting the survey to manually proceed, or contact the departmental secretary.
If you are enrolled in more than one degree programme, contact the department secretary to indicate both matricula. If the problem persists, uninstall and reinstall the app.