What is an Absent subscriber?

Absent subscriber: Absent subscriber due to the phone being switched off, due to the phone being out of coverage, due to roaming restriction/restricted area.

Absent subscriber (HLR Access Denied: Postponed): Subscriber cannot be reached at the time of broadcast or unknown subscriber. The Home Location Register is a database. It provides routing information for MT (Mobile Terminated) calls and SMS (Short Message Service) 

Absent subscriber (No acknowledgment): Absent subscriber due to the phone being switched off, due to phone out of coverage, due to roaming restriction/restricted area without acknowledgment.

Absent subscriber (Destination resource shortage): The message is rejected because there was no paging response, the IMSI record is marked detached, or the MS is subject to roaming restrictions.

Absent subscriber (SMS delivery postponed): The user's mobile number is not reachable or out of the network coverage area.

Absent subscriber (Destination out of service): Mobile number barred at the carrier end.

Absent subscriber SM: Out of coverage area (or) switched off. The error might be due to the poor network coverage area and the same flag was updated in the HLR.

Note: Important Abbreviations: