The specified url cannot be found on postback asp net windows authentication


ASP.NET is a popular programming language used for building dynamic web . It provides a framework for developing web pages and web services, and it is widely used for creating enterprise-level applications. However, like any programming language, ASP.NET can sometimes present challenges that need to be solved. In this article, we will address the question of the URL not being found on in ASP.NET with examples.

The Problem

One common issue that face in ASP.NET is when a specified URL cannot be found on postback. This typically occurs when a user submits a form or performs an action that triggers a postback, and the server is unable to locate the specified URL to handle the request. This can result in an error message or unexpected behavior for the user.

Possible Causes

There can be several reasons why a specified URL cannot be found on postback in ASP.NET. Some possible causes include:

  • Incorrect URL mapping or routing configuration
  • Missing or incorrect form action attribute
  • Invalid or expired session
  • Authentication or authorization issues


To solve the problem of a specified URL not being found on postback in ASP.NET, you can follow these steps:

Step 1: Check URL Mapping or Routing Configuration

The first step is to ensure that the URL mapping or routing configuration is correct. This involves checking the routing table or configuration file to ensure that the specified URL is mapped to the controller or handler. Here is an example of how to check the routing configuration in ASP.NET:

// Check routing configuration
    name: "Default",
    url: "{controller}/{action}/{id}",
    defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }

Step 2: Verify Form Action Attribute

The next step is to verify the form action attribute in your HTML . The form action attribute specifies the URL to which the form data should be submitted. Make sure that the action attribute is correctly set to the desired URL. Here is an example of how to set the form action attribute in ASP.NET:

// Verify form action attribute
// Form fields

Step 3: Check Session State

If your application relies on session state, it is important to check if the session is valid and not expired. You can do this by checking the session state in your code and redirecting the user to an appropriate page if the session is invalid. Here is an example of how to check the session state in ASP.NET:

// Check session state
if (Session["UserID"] == null)
    // Redirect to  page

Step 4: Verify Authentication and Authorization

Lastly, it is important to verify the authentication and authorization settings in your ASP.NET application. Ensure that the user has the necessary permissions to access the specified URL. You can use the built-in authentication and authorization mechanisms provided by ASP.NET or implement custom logic based on your requirements. Here is an example of how to verify authentication and authorization in ASP.NET:

// Verify authentication and authorization
if (!User.Identity.)
    // Redirect to login page


In this article, we have addressed the question of the specified URL not being found on postback in ASP.NET. We have discussed possible causes for this issue and provided a step-by-step solution to resolve it. By these steps and ensuring correct configuration, form action attribute, session state, and authentication/authorization settings, you can overcome this problem and ensure a smooth user experience in your ASP.NET application.

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