不在届け
Meanings
1
notice of absence; mail hold request
A form submitted to the post office to request that mail be held during a long absence, such as a trip.
Before a long trip, I submitted a notice of absence to the post office.
2
missed-delivery notice
A notice left by a delivery service when a package could not be delivered because the recipient was absent.
When I got home, a missed-delivery notice from the courier was stuck on my door.