diff --git a/lib/src/clixon_validate.c b/lib/src/clixon_validate.c
index 5ff366c9..11fe11f0 100644
--- a/lib/src/clixon_validate.c
+++ b/lib/src/clixon_validate.c
@@ -669,8 +669,24 @@ check_list_key(cxobj     *xt,
         while ((cvi = cvec_each(cvk, cvi)) != NULL) {
             keyname = cv_string_get(cvi);           
             if (xml_find_type(xt, NULL, keyname, CX_ELMNT) == NULL){
-                if (xret && netconf_missing_element_xml(xret, "application", keyname, "Mandatory key") < 0)
-                    goto done;
+                if (xret){
+                    cbuf         *cb = NULL;
+                    yang_stmt    *ymod;
+                    enum rfc_6020 keyw;
+
+                    if ((cb = cbuf_new()) == NULL){
+                        clicon_err(OE_UNIX, errno, "cbuf_new"); 
+                        goto done;
+                    }
+                    ymod = ys_module(yt);
+                    keyw = yang_keyword_get(yt);
+                    cprintf(cb, "Mandatory key in '%s %s' in %s.yang:%d",
+                            yang_key2str(keyw), xml_name(xt), yang_argument_get(ymod),
+                            yang_linenum_get(yc));
+                    if (netconf_missing_element_xml(xret, "application", keyname, cbuf_get(cb)) < 0)
+                        goto done;
+                    cbuf_free(cb);
+                }
                 goto fail;
             }
         }
diff --git a/test/test_netconf.sh b/test/test_netconf.sh
index c50416c1..dc4de610 100755
--- a/test/test_netconf.sh
+++ b/test/test_netconf.sh
@@ -223,7 +223,7 @@ new "Re-Delete eth/0/0 using none should generate error"
 expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><interfaces xmlns=\"urn:ietf:params:xml:ns:yang:ietf-interfaces\" xmlns:nc=\"urn:ietf:params:xml:ns:netconf:base:1.0\"><interface nc:operation=\"delete\"><name>eth/0/0</name><type>ex:eth</type></interface></interfaces></config><default-operation>none</default-operation> </edit-config></rpc>" "<rpc-reply $DEFAULTNS><rpc-error>" ""
 
 new "Add interface without key"
-expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><interfaces xmlns=\"urn:ietf:params:xml:ns:yang:ietf-interfaces\" xmlns:nc=\"urn:ietf:params:xml:ns:netconf:base:1.0\"><interface nc:operation=\"create\"><type>ex:eth</type></interface></interfaces></config><default-operation>none</default-operation> </edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>missing-element</error-tag><error-info><bad-element>name</bad-element></error-info><error-severity>error</error-severity><error-message>Mandatory key</error-message></rpc-error></rpc-reply>"
+expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><edit-config><target><candidate/></target><config><interfaces xmlns=\"urn:ietf:params:xml:ns:yang:ietf-interfaces\" xmlns:nc=\"urn:ietf:params:xml:ns:netconf:base:1.0\"><interface nc:operation=\"create\"><type>ex:eth</type></interface></interfaces></config><default-operation>none</default-operation> </edit-config></rpc>" "" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>missing-element</error-tag><error-info><bad-element>name</bad-element></error-info><error-severity>error</error-severity><error-message>Mandatory key in 'list interface' in ietf-interfaces.yang:107</error-message></rpc-error></rpc-reply>"
 
 new "netconf discard-changes"
 expecteof_netconf "$clixon_netconf -qf $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><discard-changes/></rpc>" "" "<rpc-reply $DEFAULTNS><ok/></rpc-reply>"
diff --git a/test/test_restconf_op.sh b/test/test_restconf_op.sh
index 6c90d286..847e4d66 100755
--- a/test/test_restconf_op.sh
+++ b/test/test_restconf_op.sh
@@ -102,7 +102,7 @@ new "wait restconf"
 wait_restconf
 
 new "restconf POST tree without key"
-expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" -d '{"example:cont1":{"interface":{"type":"regular"}}}' $RCPROTO://localhost/restconf/data)" 0 "HTTP/$HVER 400" '{"ietf-restconf:errors":{"error":{"error-type":"application","error-tag":"missing-element","error-info":{"bad-element":"name"},"error-severity":"error","error-message":"Mandatory key"}}}'
+expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" -d '{"example:cont1":{"interface":{"type":"regular"}}}' $RCPROTO://localhost/restconf/data)" 0 "HTTP/$HVER 400" "{\"ietf-restconf:errors\":{\"error\":{\"error-type\":\"application\",\"error-tag\":\"missing-element\",\"error-info\":{\"bad-element\":\"name\"},\"error-severity\":\"error\",\"error-message\":\"Mandatory key in 'list interface' in example.yang:7\"}}}"
 
 new "restconf POST initial tree"
 expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" -d '{"example:cont1":{"interface":{"name":"local0","type":"regular"}}}' $RCPROTO://localhost/restconf/data)" 0 "HTTP/$HVER 201"
@@ -134,7 +134,7 @@ new "restconf POST interface without mandatory type"
 expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" $RCPROTO://localhost/restconf/data/example:cont1 -d '{"example:interface":{"name":"TEST"}}')" 0 "HTTP/$HVER 400" '{"ietf-restconf:errors":{"error":{"error-type":"application","error-tag":"missing-element","error-info":{"bad-element":"type"},"error-severity":"error","error-message":"Mandatory variable of interface in module example"}}}'
 
 new "restconf POST interface without mandatory key"
-expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" $RCPROTO://localhost/restconf/data/example:cont1 -d '{"example:interface":{"type":"regular"}}')" 0 "HTTP/$HVER 400" '{"ietf-restconf:errors":{"error":{"error-type":"application","error-tag":"missing-element","error-info":{"bad-element":"name"},"error-severity":"error","error-message":"Mandatory key"}}}'
+expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" $RCPROTO://localhost/restconf/data/example:cont1 -d '{"example:interface":{"type":"regular"}}')" 0 "HTTP/$HVER 400" "{\"ietf-restconf:errors\":{\"error\":{\"error-type\":\"application\",\"error-tag\":\"missing-element\",\"error-info\":{\"bad-element\":\"name\"},\"error-severity\":\"error\",\"error-message\":\"Mandatory key in 'list interface' in example.yang:7\"}}}"
 
 new "restconf POST interface"
 expectpart "$(curl $CURLOPTS -X POST -H "Content-Type: application/yang-data+json" -d '{"example:interface":{"name":"TEST","type":"eth0"}}' $RCPROTO://localhost/restconf/data/example:cont1)" 0 "HTTP/$HVER 201"
diff --git a/test/test_rpc.sh b/test/test_rpc.sh
index c34034d0..d70d8b28 100755
--- a/test/test_rpc.sh
+++ b/test/test_rpc.sh
@@ -345,7 +345,7 @@ expecteof_netconf "$clixon_netconf -qef $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS
 
 LIST='<u1 xmlns="urn:example:clixon"><uk>bar</uk><val>1</val></u1><u1 xmlns="urn:example:clixon"><val>2</val></u1>'
 new "netconf example rpc input key list without key (should fail)"
-expecteof_netconf "$clixon_netconf -qef $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><example xmlns=\"urn:example:clixon\"><x>mandatory</x>$LIST</example></rpc>" "" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>missing-element</error-tag><error-info><bad-element>uk</bad-element></error-info><error-severity>error</error-severity><error-message>Mandatory key</error-message></rpc-error></rpc-reply>"
+expecteof_netconf "$clixon_netconf -qef $cfg" 0 "$DEFAULTHELLO" "<rpc $DEFAULTNS><example xmlns=\"urn:example:clixon\"><x>mandatory</x>$LIST</example></rpc>" "" "<rpc-reply $DEFAULTNS><rpc-error><error-type>application</error-type><error-tag>missing-element</error-tag><error-info><bad-element>uk</bad-element></error-info><error-severity>error</error-severity><error-message>Mandatory key in 'list u1' in clixon-example.yang:62</error-message></rpc-error></rpc-reply>"
 
 LIST='<u1 xmlns="urn:example:clixon"><uk>bar</uk><val>1</val></u1><u1 xmlns="urn:example:clixon"><uk>bar</uk><val>2</val></u1>'
 new "netconf example rpc input list with non-unique keys (should fail)"