diff --git a/src/sgwc/pfcp-path.c b/src/sgwc/pfcp-path.c
index fb4a5490b7..97729df958 100644
--- a/src/sgwc/pfcp-path.c
+++ b/src/sgwc/pfcp-path.c
@@ -189,7 +189,7 @@ static void sess_timeout(ogs_pfcp_xact_t *pfcp_xact, void *data)
         gtp_cause = OGS_GTP1_CAUSE_NETWORK_FAILURE;
         break;
     case 2:
-        gtp_cause = OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+        gtp_cause = OGS_GTP2_CAUSE_TIMED_OUT_REQUEST;
         break;
     }    
 
diff --git a/src/smf/gsm-sm.c b/src/smf/gsm-sm.c
index 741557443c..024d06a4e1 100644
--- a/src/smf/gsm-sm.c
+++ b/src/smf/gsm-sm.c
@@ -53,7 +53,7 @@ static uint8_t gtp_cause_from_diameter(uint8_t gtp_version,
         case OGS_DIAM_UNKNOWN_SESSION_ID:
             return OGS_GTP2_CAUSE_APN_ACCESS_DENIED_NO_SUBSCRIPTION;
         case ER_DIAMETER_UNABLE_TO_DELIVER:
-            return OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+            return OGS_GTP2_CAUSE_UE_NOT_AUTHORISED_BY_OCS_OR_EXTERNAL_AAA_SERVER;
         }
         break;
     }
@@ -726,7 +726,7 @@ void smf_gsm_state_wait_pfcp_establishment(ogs_fsm_t *s, smf_event_t *e)
                 ogs_gtp_xact_t *gtp_xact = (ogs_gtp_xact_t *) sess->timeout_xact->assoc_xact;
                 uint8_t gtp_cause = (gtp_xact->gtp_version == 1) ?
                         OGS_GTP1_CAUSE_NETWORK_FAILURE :
-                        OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+                        OGS_GTP2_CAUSE_TIMED_OUT_REQUEST;
                 send_gtp_create_err_msg(sess, gtp_xact, gtp_cause);
             } else {
                 OGS_FSM_TRAN(s, smf_gsm_state_5gc_n1_n2_reject);
@@ -1284,7 +1284,7 @@ void smf_gsm_state_operational(ogs_fsm_t *s, smf_event_t *e)
                 ogs_gtp_xact_t *gtp_xact = (ogs_gtp_xact_t *) sess->timeout_xact->assoc_xact;
                 uint8_t gtp_cause = (gtp_xact->gtp_version == 1) ?
                         OGS_GTP1_CAUSE_NETWORK_FAILURE :
-                        OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+                        OGS_GTP2_CAUSE_TIMED_OUT_REQUEST;
                 send_gtp_create_err_msg(sess, gtp_xact, gtp_cause);
             } else {
                 OGS_FSM_TRAN(s, smf_gsm_state_5gc_n1_n2_reject);
@@ -1473,7 +1473,7 @@ void smf_gsm_state_wait_pfcp_deletion(ogs_fsm_t *s, smf_event_t *e)
                 ogs_gtp_xact_t *gtp_xact = (ogs_gtp_xact_t *) sess->timeout_xact->assoc_xact;
                 uint8_t gtp_cause = (gtp_xact->gtp_version == 1) ?
                         OGS_GTP1_CAUSE_NETWORK_FAILURE :
-                        OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+                        OGS_GTP2_CAUSE_TIMED_OUT_REQUEST;
                 send_gtp_delete_err_msg(sess, gtp_xact, gtp_cause);
             } else {
                 ogs_error("5GC Session Deletion timeout not written");
diff --git a/src/smf/s5c-handler.c b/src/smf/s5c-handler.c
index f1333ff89d..bdabeba190 100644
--- a/src/smf/s5c-handler.c
+++ b/src/smf/s5c-handler.c
@@ -137,7 +137,7 @@ uint8_t smf_s5c_handle_create_session_request(
 
     if (!ogs_diam_app_connected(OGS_DIAM_GX_APPLICATION_ID)) {
         ogs_error("No Gx Diameter Peer");
-        cause_value = OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+        cause_value = OGS_GTP2_CAUSE_UE_NOT_AUTHORISED_BY_OCS_OR_EXTERNAL_AAA_SERVER;
     }
     switch (sess->gtp_rat_type) {
     case OGS_GTP2_RAT_TYPE_EUTRAN:
@@ -154,7 +154,7 @@ uint8_t smf_s5c_handle_create_session_request(
     case OGS_GTP2_RAT_TYPE_WLAN:
         if (!ogs_diam_app_connected(OGS_DIAM_S6B_APPLICATION_ID)) {
             ogs_error("No S6b Diameter Peer");
-            cause_value = OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+            cause_value = OGS_GTP2_CAUSE_UE_NOT_AUTHORISED_BY_OCS_OR_EXTERNAL_AAA_SERVER;
         }
         if (req->bearer_contexts_to_be_created[0].
                 s2b_u_epdg_f_teid_5.presence == 0) {
@@ -426,13 +426,13 @@ uint8_t smf_s5c_handle_delete_session_request(
 
     if (!ogs_diam_app_connected(OGS_DIAM_GX_APPLICATION_ID)) {
         ogs_error("No Gx Diameter Peer");
-        return OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+        return OGS_GTP2_CAUSE_UE_NOT_AUTHORISED_BY_OCS_OR_EXTERNAL_AAA_SERVER;
     }
 
     if (sess->gtp_rat_type == OGS_GTP2_RAT_TYPE_WLAN) {
         if (!ogs_diam_app_connected(OGS_DIAM_S6B_APPLICATION_ID)) {
             ogs_error("No S6b Diameter Peer");
-            return OGS_GTP2_CAUSE_REMOTE_PEER_NOT_RESPONDING;
+            return OGS_GTP2_CAUSE_UE_NOT_AUTHORISED_BY_OCS_OR_EXTERNAL_AAA_SERVER;
         }
     }