you should set the holiday greeting for you main auto attendant ..if there is no call handler you should set the holiday greeting for opening greetingas every call will land opening greeting if unity did not find the user or call handler with called ...

best way would be use broadcast hunting in line group

Please go to user /system call handler edit >> greeting >> enable holiday greeting (chose personal recording)step 2 >> System Settings >>Holiday Schedules (add all the necessary holidays)step 3 >> user /system call handler >> Active Schedule >> view ...