Section: G.1 Causes related to MS identification
Content: Cause value = 2 IMSI unknown in HLR This cause is sent to the MS if the MS is not known (registered) in the HLR, or if the MS has packet only subscription (see 3GPP TS 29.272[ Evolved Packet System (EPS); Mobility Management Entity (MME) and Serving GPRS Support Node (SGSN) related interfaces based on Diameter protocol ]  [150]). This cause code does not affect operation of the GPRS service, although is may be used by a GMM procedure. Cause value = 3 Illegal MS This cause is sent to the MS when the network refuses service to the MS either because an identity of the MS is not acceptable to the network or because the MS does not pass the authentication check, i.e. the SRES received from the MS is different from that generated by the network. When used by an MM procedure, except the authentication procedure, this cause does not affect operation of the GPRS service. Cause value = 4 IMSI unknown in VLR This cause is sent to the MS when the given IMSI is not known at the VLR. Cause value = 5 IMEI not accepted This cause is sent to the MS if the network does not accept emergency call establishment using an IMEI or not accept attach procedure for emergency services using an IMEI. Cause value = 6 Illegal ME This cause is sent to the MS if the ME used is not acceptable to the network, e.g. prohibit listed When used by an MM procedure, this cause does not affect operation of the GPRS service.