Setting/automailsendoffset

The Trigger Time sets the time relative to the Trigger Event when the action should first trigger.

A positive Trigger Time value is after the event and a negative value is before the event.

To trigger an action before Check-in requires a negative Trigger Time value when using the Check-in Trigger Event.

A negative Trigger Time in combination with the Booking Trigger Event is not valid (trigger before booking is not possible).

For "Booking" the system uses the actual booking time for calculation. For "Check-in" and "Check-out" it uses midnight of the day GMT.