diff --git a/src/IdentityServer/Endpoints/Results/BackchannelAuthenticationResult.cs b/src/IdentityServer/Endpoints/Results/BackchannelAuthenticationResult.cs
index c9198a893..b518bc6b1 100644
--- a/src/IdentityServer/Endpoints/Results/BackchannelAuthenticationResult.cs
+++ b/src/IdentityServer/Endpoints/Results/BackchannelAuthenticationResult.cs
@@ -71,7 +71,7 @@ await context.Response.WriteJsonAsync(new SuccessResultDto
                 expires_in = result.Response.ExpiresIn,
                 interval = result.Response.Interval,
                 
-                Properties = result.Response.Custom
+                Custom = result.Response.Custom
             });
         }
     }
@@ -84,7 +84,7 @@ internal class SuccessResultDto
         public int interval { get; set; }
 
         [JsonExtensionData]
-        public Dictionary<string, object> Properties { get; set; }
+        public Dictionary<string, object> Custom { get; set; }
 #pragma warning restore IDE1006 // Naming Styles
     }