diff --git a/src/HotChocolate/Core/src/Types/Types/Introspection/__Type.cs b/src/HotChocolate/Core/src/Types/Types/Introspection/__Type.cs
index 90865c23346..c980c9fb9f7 100644
--- a/src/HotChocolate/Core/src/Types/Types/Introspection/__Type.cs
+++ b/src/HotChocolate/Core/src/Types/Types/Introspection/__Type.cs
@@ -125,7 +125,7 @@ type switch
 
             public string? GetSpecifiedBy([Parent] IType type) =>
                 type is ScalarType scalar
-                    ? scalar.SpecifiedBy.ToString()
+                    ? scalar.SpecifiedBy?.ToString()
                     : null;
         }