https://github.com/ParsePlatform/parse-server/pull/2114

Author: caoer

src/Controllers/DatabaseController.js

@@ -121,7 +121,7 @@ DatabaseController.prototype.loadSchema = function() {
 DatabaseController.prototype.redirectClassNameForKey = function(className, key) {
   return this.loadSchema().then((schema) => {
     var t = schema.getExpectedType(className, key);
-    if (t.type == 'Relation') {
+    if (t && t.type == 'Relation') {
       return t.targetClass;
     } else {
       return className;