diff --git a/src/activities/Elsa.Activities.Http/JavaScript/HttpEndpointTypeDefinitionRenderer.cs b/src/activities/Elsa.Activities.Http/JavaScript/HttpEndpointTypeDefinitionRenderer.cs
index bfc93e00f..d584344f8 100644
--- a/src/activities/Elsa.Activities.Http/JavaScript/HttpEndpointTypeDefinitionRenderer.cs
+++ b/src/activities/Elsa.Activities.Http/JavaScript/HttpEndpointTypeDefinitionRenderer.cs
@@ -64,8 +64,8 @@ namespace Elsa.Activities.Http.JavaScript
                 return;
             }
 
-            var targetTypeName = activityDefinition.Properties.First(x => x.Name == nameof(HttpEndpoint.TargetType)).Expressions.Values.First();
-            var targetTypeSchema = activityDefinition.Properties.First(x => x.Name == nameof(HttpEndpoint.Schema)).Expressions.Values.First();
+            var targetTypeName = activityDefinition.Properties.First(x => x.Name == nameof(HttpEndpoint.TargetType)).Expressions.Values.FirstOrDefault();
+            var targetTypeSchema = activityDefinition.Properties.First(x => x.Name == nameof(HttpEndpoint.Schema)).Expressions.Values.FirstOrDefault();
             var typeScriptType = notification.GetTypeScriptType(propertyType);
 
             if (!string.IsNullOrWhiteSpace(targetTypeName))