diff --git a/lib/asn1c/util/conv.c b/lib/asn1c/util/conv.c
index f86f5f5a80..fdcbeeacb3 100644
--- a/lib/asn1c/util/conv.c
+++ b/lib/asn1c/util/conv.c
@@ -171,8 +171,10 @@ int ogs_asn_BIT_STRING_to_ip(BIT_STRING_t *bit_string, ogs_ip_t *ip)
         ip->ipv6 = 1;
         memcpy(&ip->addr6, bit_string->buf, OGS_IPV6_LEN);
         ogs_debug("    IPv6[%s]", OGS_INET_NTOP(&ip->addr6, buf));
-    } else
-        ogs_assert_if_reached();
+    } else {
+        ogs_error("ogs_asn_BIT_STRING_to_ip(size=%d) failed", bit_string->size);
+        return OGS_ERROR;
+    }
 
     ip->len = bit_string->size;
 
diff --git a/src/mme/s1ap-handler.c b/src/mme/s1ap-handler.c
index a8c71c6304..d871a34d43 100644
--- a/src/mme/s1ap-handler.c
+++ b/src/mme/s1ap-handler.c
@@ -730,7 +730,15 @@ void s1ap_handle_initial_context_setup_response(
             bearer->enb_s1u_teid = be32toh(bearer->enb_s1u_teid);
             rv = ogs_asn_BIT_STRING_to_ip(
                     &e_rab->transportLayerAddress, &bearer->enb_s1u_ip);
-            ogs_assert(rv == OGS_OK);
+            if (rv != OGS_OK) {
+                ogs_error("No transportLayerAddress [%d]",
+                        (int)e_rab->e_RAB_ID);
+                ogs_assert(OGS_OK ==
+                    s1ap_send_error_indication2(mme_ue,
+                        S1AP_Cause_PR_protocol,
+                        S1AP_CauseProtocol_abstract_syntax_error_falsely_constructed_message));
+                return;
+            }
 
             ogs_debug("    EBI[%d] ENB-S1U-TEID[%d]",
                     bearer->ebi, bearer->enb_s1u_teid);
@@ -1186,8 +1194,16 @@ void s1ap_handle_e_rab_setup_response(
                 sizeof(bearer->enb_s1u_teid));
             bearer->enb_s1u_teid = be32toh(bearer->enb_s1u_teid);
             rv = ogs_asn_BIT_STRING_to_ip(
-                &e_rab->transportLayerAddress, &bearer->enb_s1u_ip);
-            ogs_assert(rv == OGS_OK);
+                    &e_rab->transportLayerAddress, &bearer->enb_s1u_ip);
+            if (rv != OGS_OK) {
+                ogs_error("No transportLayerAddress [%d]",
+                        (int)e_rab->e_RAB_ID);
+                ogs_assert(OGS_OK ==
+                    s1ap_send_error_indication2(mme_ue,
+                        S1AP_Cause_PR_protocol,
+                        S1AP_CauseProtocol_abstract_syntax_error_falsely_constructed_message));
+                return;
+            }
 
             ogs_debug("    EBI[%d]", bearer->ebi);
 
@@ -1661,7 +1677,15 @@ void s1ap_handle_e_rab_modification_indication(
         bearer->enb_s1u_teid = be32toh(bearer->enb_s1u_teid);
         rv = ogs_asn_BIT_STRING_to_ip(
                 &e_rab->transportLayerAddress, &bearer->enb_s1u_ip);
-        ogs_expect(rv == OGS_OK);
+        if (rv != OGS_OK) {
+            ogs_error("No transportLayerAddress [%d]",
+                    (int)e_rab->e_RAB_ID);
+            ogs_assert(OGS_OK ==
+                s1ap_send_error_indication2(mme_ue,
+                    S1AP_Cause_PR_protocol,
+                    S1AP_CauseProtocol_abstract_syntax_error_falsely_constructed_message));
+            return;
+        }
 
         GTP_COUNTER_INCREMENT(
                 mme_ue, GTP_COUNTER_MODIFY_BEARER_BY_E_RAB_MODIFICATION);
@@ -1925,7 +1949,15 @@ void s1ap_handle_path_switch_request(
         bearer->enb_s1u_teid = be32toh(bearer->enb_s1u_teid);
         rv = ogs_asn_BIT_STRING_to_ip(
                 &e_rab->transportLayerAddress, &bearer->enb_s1u_ip);
-        ogs_expect(rv == OGS_OK);
+        if (rv != OGS_OK) {
+            ogs_error("No transportLayerAddress [%d]",
+                    (int)e_rab->e_RAB_ID);
+            ogs_assert(OGS_OK ==
+                s1ap_send_error_indication2(mme_ue,
+                    S1AP_Cause_PR_protocol,
+                    S1AP_CauseProtocol_abstract_syntax_error_falsely_constructed_message));
+            return;
+        }
 
         GTP_COUNTER_INCREMENT(
                 mme_ue, GTP_COUNTER_MODIFY_BEARER_BY_PATH_SWITCH);
@@ -2352,7 +2384,15 @@ void s1ap_handle_handover_request_ack(
         bearer->target_s1u_teid = be32toh(bearer->target_s1u_teid);
         rv = ogs_asn_BIT_STRING_to_ip(
                 &e_rab->transportLayerAddress, &bearer->target_s1u_ip);
-        ogs_assert(rv == OGS_OK);
+        if (rv != OGS_OK) {
+            ogs_error("No transportLayerAddress [%d]",
+                    (int)e_rab->e_RAB_ID);
+            ogs_assert(OGS_OK ==
+                s1ap_send_error_indication2(mme_ue,
+                    S1AP_Cause_PR_protocol,
+                    S1AP_CauseProtocol_abstract_syntax_error_falsely_constructed_message));
+            return;
+        }
 
         if (e_rab->dL_transportLayerAddress && e_rab->dL_gTP_TEID) {
             ogs_assert(e_rab->dL_gTP_TEID->buf);
@@ -2362,7 +2402,15 @@ void s1ap_handle_handover_request_ack(
             bearer->enb_dl_teid = be32toh(bearer->enb_dl_teid);
             rv = ogs_asn_BIT_STRING_to_ip(
                     e_rab->dL_transportLayerAddress, &bearer->enb_dl_ip);
-            ogs_assert(rv == OGS_OK);
+            if (rv != OGS_OK) {
+                ogs_error("No dL_transportLayerAddress [%d]",
+                        (int)e_rab->e_RAB_ID);
+                ogs_assert(OGS_OK ==
+                    s1ap_send_error_indication2(mme_ue,
+                        S1AP_Cause_PR_protocol,
+                        S1AP_CauseProtocol_abstract_syntax_error_falsely_constructed_message));
+                return;
+            }
         }
 
         if (e_rab->uL_TransportLayerAddress && e_rab->uL_GTP_TEID) {
@@ -2373,7 +2421,15 @@ void s1ap_handle_handover_request_ack(
             bearer->enb_ul_teid = be32toh(bearer->enb_ul_teid);
             rv = ogs_asn_BIT_STRING_to_ip(
                     e_rab->uL_TransportLayerAddress, &bearer->enb_ul_ip);
-            ogs_assert(rv == OGS_OK);
+            if (rv != OGS_OK) {
+                ogs_error("No uL_transportLayerAddress [%d]",
+                        (int)e_rab->e_RAB_ID);
+                ogs_assert(OGS_OK ==
+                    s1ap_send_error_indication2(mme_ue,
+                        S1AP_Cause_PR_protocol,
+                        S1AP_CauseProtocol_abstract_syntax_error_falsely_constructed_message));
+                return;
+            }
         }
     }
 
diff --git a/src/smf/ngap-handler.c b/src/smf/ngap-handler.c
index e9ad851ecc..84d6f93690 100644
--- a/src/smf/ngap-handler.c
+++ b/src/smf/ngap-handler.c
@@ -91,8 +91,15 @@ int ngap_handle_pdu_session_resource_setup_response_transfer(
         goto cleanup;
     }
 
-    ogs_asn_BIT_STRING_to_ip(
+    rv = ogs_asn_BIT_STRING_to_ip(
             &gTPTunnel->transportLayerAddress, &gnb_n3_ip);
+    if (rv != OGS_OK) {
+        ogs_error("[%s:%d] No transportLayerAddress", smf_ue->supi, sess->psi);
+        smf_sbi_send_sm_context_update_error(stream,
+                OGS_SBI_HTTP_STATUS_BAD_REQUEST,
+                "No transportLayerAddress", smf_ue->supi, NULL, NULL);
+        goto cleanup;
+    }
     ogs_asn_OCTET_STRING_to_uint32(&gTPTunnel->gTP_TEID, &gnb_n3_teid);
 
     /* Need to Update? */
@@ -406,7 +413,15 @@ int ngap_handle_path_switch_request_transfer(
         goto cleanup;
     }
 
-    ogs_asn_BIT_STRING_to_ip(&gTPTunnel->transportLayerAddress, &gnb_n3_ip);
+    rv = ogs_asn_BIT_STRING_to_ip(
+            &gTPTunnel->transportLayerAddress, &gnb_n3_ip);
+    if (rv != OGS_OK) {
+        ogs_error("[%s:%d] No transportLayerAddress", smf_ue->supi, sess->psi);
+        smf_sbi_send_sm_context_update_error(stream,
+                OGS_SBI_HTTP_STATUS_BAD_REQUEST,
+                "No transportLayerAddress", smf_ue->supi, NULL, NULL);
+        goto cleanup;
+    }
     ogs_asn_OCTET_STRING_to_uint32(&gTPTunnel->gTP_TEID, &gnb_n3_teid);
 
     /* Need to Update? */
@@ -578,8 +593,15 @@ int ngap_handle_handover_request_ack(
         goto cleanup;
     }
 
-    ogs_asn_BIT_STRING_to_ip(&gTPTunnel->transportLayerAddress,
+    rv = ogs_asn_BIT_STRING_to_ip(&gTPTunnel->transportLayerAddress,
             &sess->handover.gnb_n3_ip);
+    if (rv != OGS_OK) {
+        ogs_error("[%s:%d] No transportLayerAddress", smf_ue->supi, sess->psi);
+        smf_sbi_send_sm_context_update_error(stream,
+                OGS_SBI_HTTP_STATUS_BAD_REQUEST,
+                "No transportLayerAddress", smf_ue->supi, NULL, NULL);
+        goto cleanup;
+    }
     ogs_asn_OCTET_STRING_to_uint32(&gTPTunnel->gTP_TEID,
             &sess->handover.gnb_n3_teid);
 
@@ -630,8 +652,16 @@ int ngap_handle_handover_request_ack(
             goto cleanup;
         }
 
-        ogs_asn_BIT_STRING_to_ip(&gTPTunnel->transportLayerAddress,
+        rv = ogs_asn_BIT_STRING_to_ip(&gTPTunnel->transportLayerAddress,
                 &sess->handover.gnb_dl_ip);
+        if (rv != OGS_OK) {
+            ogs_error("[%s:%d] No transportLayerAddress",
+                    smf_ue->supi, sess->psi);
+            smf_sbi_send_sm_context_update_error(stream,
+                    OGS_SBI_HTTP_STATUS_BAD_REQUEST,
+                    "No transportLayerAddress", smf_ue->supi, NULL, NULL);
+            goto cleanup;
+        }
         ogs_asn_OCTET_STRING_to_uint32(&gTPTunnel->gTP_TEID,
                 &sess->handover.gnb_dl_teid);