diff --git a/lib/northbound.c b/lib/northbound.c
index 63062ee336..35d0596ed4 100644
--- a/lib/northbound.c
+++ b/lib/northbound.c
@@ -908,7 +908,7 @@ static int nb_candidate_edit_tree_add(struct nb_config *candidate,
 			if (operation == NB_OP_CREATE_EXCL) {
 				snprintf(errmsg, errmsg_len,
 					 "Data already exists");
-				ret = NB_ERR;
+				ret = NB_ERR_EXISTS;
 				goto done;
 			}
 
@@ -995,7 +995,7 @@ static int nb_candidate_edit_tree_del(struct nb_config *candidate,
 	if (!dnode || (dnode->flags & LYD_DEFAULT)) {
 		if (operation == NB_OP_DELETE) {
 			snprintf(errmsg, errmsg_len, "Data missing");
-			return NB_ERR;
+			return NB_ERR_NOT_FOUND;
 		} else
 			return NB_OK;
 	}
@@ -2605,6 +2605,8 @@ const char *nb_err_name(enum nb_error error)
 		return "no changes";
 	case NB_ERR_NOT_FOUND:
 		return "element not found";
+	case NB_ERR_EXISTS:
+		return "element already exists";
 	case NB_ERR_LOCKED:
 		return "resource is locked";
 	case NB_ERR_VALIDATION:
diff --git a/lib/northbound.h b/lib/northbound.h
index da5f5be1ee..b311affa31 100644
--- a/lib/northbound.h
+++ b/lib/northbound.h
@@ -678,6 +678,7 @@ enum nb_error {
 	NB_ERR,
 	NB_ERR_NO_CHANGES,
 	NB_ERR_NOT_FOUND,
+	NB_ERR_EXISTS,
 	NB_ERR_LOCKED,
 	NB_ERR_VALIDATION,
 	NB_ERR_RESOURCE,
diff --git a/mgmtd/mgmt_fe_adapter.h b/mgmtd/mgmt_fe_adapter.h
index 61d6cfae13..5a7dec3e6f 100644
--- a/mgmtd/mgmt_fe_adapter.h
+++ b/mgmtd/mgmt_fe_adapter.h
@@ -194,7 +194,7 @@ extern int mgmt_fe_adapter_send_rpc_reply(uint64_t session_id, uint64_t txn_id,
  *     unlock: implicit-lock flag was set in the request
  *     commit: implicit-commit flag was set in the request
  *     xpath: the xpath of the data node that was created
- *     error: the error code, zero for successful request
+ *     error: >0 LY_ERR, < 0 -errno
  *     errstr: the error string, if error is non-zero
  */
 extern int mgmt_fe_adapter_send_edit_reply(uint64_t session_id, uint64_t txn_id,
@@ -210,7 +210,7 @@ extern int mgmt_fe_adapter_send_edit_reply(uint64_t session_id, uint64_t txn_id,
  * Args:
  *	txn_id: the txn_id this error pertains to.
  *	short_circuit_ok: True if OK to short-circuit the call.
- *	error: An integer error value.
+ *      error: >0 LY_ERR, < 0 -errno
  *	errfmt: An error format string (i.e., printfrr)
  *      ...: args for use by the `errfmt` format string.
  *
diff --git a/mgmtd/mgmt_txn.c b/mgmtd/mgmt_txn.c
index ed133243a1..53d9f5c3fa 100644
--- a/mgmtd/mgmt_txn.c
+++ b/mgmtd/mgmt_txn.c
@@ -1335,7 +1335,8 @@ static int txn_get_tree_data_done(struct mgmt_txn_ctx *txn,
 			  " req_id %" PRIu64 " to requested type %u",
 			  txn->txn_id, req_id, get_tree->result_type);
 
-		(void)mgmt_fe_adapter_txn_error(txn->txn_id, req_id, false, ret,
+		(void)mgmt_fe_adapter_txn_error(txn->txn_id, req_id, false,
+						errno_from_nb_error(ret),
 						"Error converting results of GETTREE");
 	}
 
@@ -1351,7 +1352,7 @@ static int txn_rpc_done(struct mgmt_txn_ctx *txn, struct mgmt_txn_req *txn_req)
 	EVENT_OFF(txn->rpc_timeout);
 
 	if (rpc->errstr)
-		mgmt_fe_adapter_txn_error(txn->txn_id, req_id, false, -1,
+		mgmt_fe_adapter_txn_error(txn->txn_id, req_id, false, -EINVAL,
 					  rpc->errstr);
 	else if (mgmt_fe_adapter_send_rpc_reply(txn->session_id, txn->txn_id,
 						req_id, rpc->result_type,
@@ -1360,7 +1361,8 @@ static int txn_rpc_done(struct mgmt_txn_ctx *txn, struct mgmt_txn_req *txn_req)
 			  " req_id %" PRIu64 " to requested type %u",
 			  txn->txn_id, req_id, rpc->result_type);
 
-		(void)mgmt_fe_adapter_txn_error(txn->txn_id, req_id, false, -1,
+		(void)mgmt_fe_adapter_txn_error(txn->txn_id, req_id, false,
+						-EINVAL,
 						"Error converting results of RPC");
 	}
 
@@ -2580,7 +2582,7 @@ int mgmt_txn_send_edit(uint64_t txn_id, uint64_t req_id,
 reply:
 	mgmt_fe_adapter_send_edit_reply(txn->session_id, txn->txn_id, req_id,
 					unlock, commit, edit->xpath_created,
-					ret ? -1 : 0, errstr);
+					errno_from_nb_error(ret), errstr);
 
 	XFREE(MTYPE_MGMTD_TXN_REQ, edit);
 
diff --git a/mgmtd/mgmt_txn.h b/mgmtd/mgmt_txn.h
index b6ca288675..37dadc0171 100644
--- a/mgmtd/mgmt_txn.h
+++ b/mgmtd/mgmt_txn.h
@@ -69,6 +69,34 @@ static inline const char *mgmt_txn_type2str(enum mgmt_txn_type type)
 	return "Unknown";
 }
 
+
+static inline int16_t errno_from_nb_error(enum nb_error ret)
+{
+	switch (ret) {
+	case NB_OK:
+		return 0;
+	case NB_ERR_NO_CHANGES:
+		return -EALREADY;
+	case NB_ERR_NOT_FOUND:
+		return -ENOENT;
+	case NB_ERR_EXISTS:
+		return -EEXIST;
+	case NB_ERR_LOCKED:
+		return -EWOULDBLOCK;
+	case NB_ERR_VALIDATION:
+		return -EINVAL;
+	case NB_ERR_RESOURCE:
+		return -ENOMEM;
+	case NB_ERR:
+	case NB_ERR_INCONSISTENCY:
+		return -EINVAL;
+	case NB_YIELD:
+	default:
+		return -EINVAL;
+	}
+}
+
+
 /* Initialise transaction module. */
 extern int mgmt_txn_init(struct mgmt_master *cm, struct event_loop *tm);