diff --git a/src/SignalR/clients/csharp/Client.Core/src/HubConnection.cs b/src/SignalR/clients/csharp/Client.Core/src/HubConnection.cs
index f52e5ba32357..956b89b8b53e 100644
--- a/src/SignalR/clients/csharp/Client.Core/src/HubConnection.cs
+++ b/src/SignalR/clients/csharp/Client.Core/src/HubConnection.cs
@@ -2419,7 +2419,7 @@ IReadOnlyList<Type> IInvocationBinder.GetParameterTypes(string methodName)
             if (!_hubConnection._handlers.TryGetValue(methodName, out var invocationHandlerList))
             {
                 Log.MissingHandler(_logger, methodName);
-                return Type.EmptyTypes;
+                throw new KeyNotFoundException($"Method with name '{methodName}' does not exist.");
             }
 
             // We use the parameter types of the first handler