diff --git a/specification/cdn/resource-manager/Microsoft.Cdn/stable/2021-06-01/cdn.json b/specification/cdn/resource-manager/Microsoft.Cdn/stable/2021-06-01/cdn.json
index 7c43a6e50939..9424586d6070 100644
--- a/specification/cdn/resource-manager/Microsoft.Cdn/stable/2021-06-01/cdn.json
+++ b/specification/cdn/resource-manager/Microsoft.Cdn/stable/2021-06-01/cdn.json
@@ -4732,8 +4732,7 @@
         },
         "cacheDuration": {
           "description": "The duration for which the content needs to be cached. Allowed format is [d.]hh:mm:ss",
-          "type": "string",
-          "format": "duration"
+          "type": "string"
         }
       }
     },