CODEWITHSUNDEEP
asp.net.netdebuggingiisvisual-studio-2017
Ilya Chernomordik
Ilya Chernomordik

Reputation: 30175

Unable to start debugging on the web server. The remote server returned an error: (404) Not Found. Error when starting debug in Visual Studio

I have set up project to be run on IIS for some time ago and when I did press F5 it did connect no problem. But recently this stopped working and I did get this error when I press F5 / press Debug->Start debugging:

Unable to start debugging on the web server. The remote server returned an error: (404) Not Found.

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Here is my settings:

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I am not sure what happened, probably some VS updates or Windows updates, but I've tried to google everywhere and nothing had worked. Attach to process works fine as before, but this simpler way stopped doing the trick.

Update:

Have tried Process Monitor to figure out what is going wrong and it looks like w3wp tries to access path MyProjectFolder\debugattach.aspx and the result is "NAME NOT FOUND". Don't know if this is the root of the problem though.

Upvotes: 25

Views: 38909

Answers (9)

gharel
gharel

Reputation: 573

Im my case this error message (VS2017) was caused by the default http binding in IIS, port 80. Instead of being empty, "hostname" contained the name of my machine.

Solution: IIS-Default site-Bindings...- port http 80 - hostname make blank, or enter localhost

Upvotes: 0

Dinesh Rajan
Dinesh Rajan

Reputation: 2584

see this also HTTP Error 404.3-Not Found in IIS 10 as it helped me (HTTP Activation need to be enabled in Windows features)

Upvotes: 0

Rinoy Ashokan
Rinoy Ashokan

Reputation: 1619

My issue was related 405 as attached below enter image description here

My issue got resolved after making my projects properties(Web and Build) as given below enter image description here

enter image description here

Upvotes: 0

GeorgeB
GeorgeB

Reputation: 848

Old post but I recently had this issue and making sure that the following settings were enabled in 'Programs and Features' (Windows 10) fixed the issue for me:

Programs and Features to enable

Upvotes: 10

Garg V
Garg V

Reputation: 39

Recently I have faced the same issue in VS2013 Professional, instantly I get error 'Unable to start debugging on web server". I observed that whenever my current page is MVC view (.cshtml) file and I start debugging , the error window prompts every time. As switch the current document in my project to controller (.cs) file, and starts debugging, it works properly. So my workaround is to debug my code I have to be on (.cs) file not on (.cshtml / web.config) file. Hope that helps!

Upvotes: 1

mahmood kabi
mahmood kabi

Reputation: 311

Another reason for this problem is that you don't run visul studio Run as administrator.

Upvotes: 0

Michael Ludlum
Michael Ludlum

Reputation: 11

This happened to me because I was using the Rewrite module to redirect to https. I was running https://localhost/WebSiteName, but had put my machine name in the https binding in IIS Mgr, Default web Site, Bindings. When I removed the machine name it worked.

Upvotes: 1

Husam Ebish
Husam Ebish

Reputation: 6758

In my case (Windows 10 & Visual Studio 2017) I had to install ASP.NET 3.5 and ASP.NET 4.7 under the Internet Information Services.

Click here to see the solution

Upvotes: 8

Ilya Chernomordik
Ilya Chernomordik

Reputation: 30175

It appears that one of my colleagues has edited the web.config and added request filtering where he has removed the "DEBUG" verb. This disallowed debugging on F5. After adding it (or removing request filtering) everything works fine.

P.S. A lot of other possible problems with similar error is described here

Upvotes: 19

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