Error 21: Facility Not Supported

The message “Facility Not Supported for SMs” typically means that a short message (SMS) operation you’re attempting to perform is not supported by the mobile switching center (MSC) or service provider’s SMS handling system.

Here’s a detailed breakdown:

Meaning

In telecom signaling (e.g., MAP or SMPP), this error often corresponds to a “facility not supported” response, which indicates that a specific feature or parameter used in the message request is not recognized or supported by the network element that received it.
For SMS (Short Message Service), this means the network doesn’t support the facility or service type requested for the subscriber or destination.

⚙️ Common Causes

1. Unsupported Feature Request

   • Attempting to use a feature like delivery receipts, concatenated messages, or port addressing that isn’t supported by the network.

2. Incorrect Service Type

   • Sending a message type or parameter combination (e.g., “MT-FSM” with an unsupported facility) not accepted by the serving MSC.

3. Network Configuration Issue

   • The SMSC or HLR is configured to disallow a certain service for that subscriber or route.

4. Subscriber Limitation

   • The destination subscriber’s profile doesn’t support SMS (e.g., data-only SIM or barred SMS service).

5. Roaming Context

   • The subscriber is roaming on a network that doesn’t support certain SMS features.