diff --git a/backend/service/ical/icalFileGeneration.go b/backend/service/ical/icalFileGeneration.go
index 2c16380..47f41d9 100644
--- a/backend/service/ical/icalFileGeneration.go
+++ b/backend/service/ical/icalFileGeneration.go
@@ -55,7 +55,7 @@ func addAlarmIfSpecified(s *goics.Component, event model.Event, mapping model.Fe
 	if mapping.Reminder {
 		a := goics.NewComponent()
 		a.SetType("VALARM")
-		a.AddProperty("TRIGGER", "-PT15M")
+		a.AddProperty("TRIGGER", "-P0DT0H15M0S")
 		a.AddProperty("ACTION", "DISPLAY")
 		a.AddProperty("DESCRIPTION", "Next course: "+replaceNameIfUserDefined(&event, mapping)+" in "+event.Rooms)
 		s.AddComponent(a)