diff --git a/src/gprs/gprs_gmm.c b/src/gprs/gprs_gmm.c
index a363c70..a86fe2b 100644
--- a/src/gprs/gprs_gmm.c
+++ b/src/gprs/gprs_gmm.c
@@ -1862,7 +1862,7 @@
 			ctx = sgsn_mm_ctx_by_imsi(mi_string);
 		if (!ctx) {
 			/* FIXME: We need to have a context for service request? */
-			reject_cause = GMM_CAUSE_NET_FAIL;
+			reject_cause = GMM_CAUSE_IMPL_DETACHED;
 			goto rejected;
 		}
 		msgid2mmctx(ctx, msg);
@@ -1875,7 +1875,7 @@
 			ctx = sgsn_mm_ctx_by_ptmsi(tmsi);
 		if (!ctx) {
 			/* FIXME: We need to have a context for service request? */
-			reject_cause = GMM_CAUSE_NET_FAIL;
+			reject_cause = GMM_CAUSE_IMPL_DETACHED;
 			goto rejected;
 		}
 		msgid2mmctx(ctx, msg);