diff --git a/o2web/source/o2_core/o2.js b/o2web/source/o2_core/o2.js
index 47d4dfdd85c592348e69a036b375bc18b6321150..2c95308340d419e96e2f350a37a2336db6ce04b1 100644
--- a/o2web/source/o2_core/o2.js
+++ b/o2web/source/o2_core/o2.js
@@ -1973,7 +1973,7 @@ if (window.Promise && !Promise.any){
                     "then": function(s){
                         if (s){
                             var r = s(p);
-                            return (r.then && o2.typeOf(r.then)=="function") ?  r : this;
+                            return (r && r.then && o2.typeOf(r.then)=="function") ?  r : this;
                         }
                         return this;
                     }
@@ -1987,7 +1987,7 @@ if (window.Promise && !Promise.any){
                     "then": function(s){
                         if (s){
                             var r = s(p);
-                            return (r.then && o2.typeOf(r.then)=="function") ?  r : this;
+                            return (r && r.then && o2.typeOf(r.then)=="function") ?  r : this;
                         }
                         return this;
                     }