ESME_RX_R_APPN in SMPP

What is ESME_RX_R_APPN?

ESME_RX_R_APPN (Error Code: 0x00000066) is an SMPP error indicating that the SMSC encountered a reject error while processing a received request. This typically means the request was intentionally rejected by the SMSC application.

Possible Causes

  • The SMSC rejected the request due to invalid parameters.
  • Message filtering rules (e.g., blacklisting, spam protection) prevented message processing.
  • Account restrictions, such as insufficient balance or permission issues.
  • Operational policies of the SMSC preventing the request from being processed.

When Does It Happen?

This error occurs when the ESME sends a request to the SMSC, and the SMSC deliberately rejects it due to policy or validation failures.

Example SMPP PDU Transaction

Request PDU (submit_sm) Sent by ESME

0000003F (Length)
00000004 (Command ID for submit_sm)
00000000 (Command Status)
00000001 (Sequence Number)
00 (Service Type)
01 (Source Address TON - International)
01 (Source Address NPI - ISDN)
31323334 00 (Source Address: "1234")
01 (Destination Address TON - International)
01 (Destination Address NPI - ISDN)
39383736 00 (Destination Address: "9876")
00 (ESM Class)
00 (Protocol ID)
00 (Priority Flag)
00000000 (Schedule Delivery Time - Not Set)
00000000 (Validity Period - Not Set)
00 (Replace If Present Flag)
00 (Sm Default Msg ID)
0005 (Message Length)
48656C6C 6F (Message: "Hello")

Response PDU (submit_sm_resp) with ESME_RX_R_APPN

00000010 (Length)
80000004 (Command ID for submit_sm_resp)
00000066 (Command Status - ESME_RX_R_APPN)
00000001 (Sequence Number)

Issue: The SMSC intentionally rejected the submit_sm request due to application-level policies.

How to Solve It?

  • Check if the destination number or message content is restricted by the SMSC.
  • Verify the sender ID and ensure it is authorized for use.
  • Ensure that the ESME account has sufficient permissions and balance.
  • Review SMSC logs for additional rejection details.
  • Contact the SMSC provider to understand why the message was rejected.

Resolving this issue typically requires coordination with the SMSC provider to determine the rejection reason and make necessary adjustments.

More information