3GPP Scout / Reference / 5GMM causes / 5GMM cause #24

TS 24.5015GMM cause

5GMM cause #24: Security mode rejected, unspecified

TS 24.501 V20.1.0Clause 9.11.3.2Value 24 (bits 0001 1000)Checked 2026-10-15

In plain words

The UE sends this cause to the network when it rejects a security mode command for unspecified reasons.

Our summary of the spec text quoted below.

What the spec says

Name in the cause table

Security mode rejected, unspecified

Source: 3GPP TS 24.501 V20.1.0, clause 9.11.3.2, table 9.11.3.2.1. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.

When it is used

This 5GMM cause is sent to the network if the security mode command is rejected by the UE for unspecified reasons.

Source: 3GPP TS 24.501 V20.1.0, clause A.3. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: 24501-k10.zip in the 3GPP archive.

Same cause in EPS (TS 24.301)

TS 24.301 defines the corresponding cause for EPS. Its page quotes the EPS wording.

How this page was made

3GPP Scout built this page from TS 24.501 V20.1.0 as indexed on 2026-10-15. The quotes are copied from the spec, and code checks each one against the stored text and the 3GPP archive file before publishing. The plain-words line was written by an AI model (GPT-6 Sol) and checked against the quotes by a second AI model from another company (Claude Opus 5.5). The official 3GPP text governs.