visual studio error :Unable to start debugging on the web server. The remote server returned an error: (403) Forbidden [duplicate]

Question

I want to run my application from IIS on my local machine. I created the virtual directory and added the application to it.When I run application from IIS it work properly but when I am trying to run through VS 2015 it throws error.

Answer 1

Please run your app using "start without debugging" to get much more information in your side.

I met this kind of error message before which was related to the visit/write access.

Running an ASP.net project with an Application Pool with a specific Identity yields "(403) Forbidden"

Answer 2

I know this is an old post, however, I have had the same problem within vs2019 after switching to IIS debugging. In my case, I was confident that IIS was set up correctly, as another application was attaching fine.

Eventially after reviewing the documentation, I discovered that your web.config may need altering to include the following attribute:

<configuration>
    <system.web>
        <compilation defaultLanguage="VB"
            debug="true"

After setting debug="true" as stated, the debugger attached fine. Just make sure you're running VS as Admin!

Other things to consider, that I have found along the way:

• Make sure you are running VS as Admin
• Ensure your IIS App pool user is correctly set up (correct read/write permissions). Apparently for .Net 4, this also includes read/write to: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files
• A good old iisreset may also help (start > 'cmd' (as admin) > type: iisreset)
• Some people have found that setting Load User Profile to false also helps. You can find this in IIS Manager > AppPools > [Your app pool] > Advanced Settings > (category) Process Model. The default will be true
• The MS document also prompts to check your connection (request) limit (also within Advanced Settings > (category) Recycling

References

• Microsoft's guide to enabling debugging (where I ultimately found my solution)
• Microsoft's troubleshooting guide

A few other things to try

• IIS error, Unable to start debugging on the webserver
• Unable to start debugging on the web server. The remote server returned an error: (404) Not Found. Error when starting debug in Visual Studio (includes a screengrab of the required Windows Features - still applicable for 2021)