94
votes

I can't solve this problem

enter image description here

I suggest I have to change c:\Windows\System32\drivers\etc\hosts file and add after

# localhost name resolution is handled within DNS itself.

the next line:

127.0.0.1       mysite.dev

but it doesn't help. Any suggestions?

Error ocсurrs when I try to open web site project in Microsoft Visual Studio 2012.

17
It is second or third google link, I got while searched solution in the Internet. It's not what I need.Dmytro

17 Answers

185
votes

More often than not, at least in my case, this happens is when a *.csproj.user file is in the project directory and has <UseIISExpress>true</UseIISExpress> in it.

Alternatively, as mentioned by Zachary Cutler you can also simply: close Visual Studio, delete the *.csproj.user file and reopen Visual Studio. This will force VS to rebuild the file.

36
votes

I've already found the solution. I just had to edit C:\Users\Administrator\Documents\IISExpress\config\applicationhost.config file, by adding my site to <sites> node.

20
votes

You can opt to install IIS locally and edit a couple of tags on .csproj File. Open you csproj file and go to section <VisualStudio> then find tag <UseIIS>True</UseIIS> it must be set as true, then go to tag: <IISUrl> and set up with the URL address where the application will be hosted for testing:

<VisualStudio>
      <FlavorProperties GUID="{349c5851-65df-11da-9384-00065b846f21}">
        <WebProjectProperties>
          <UseIIS>True</UseIIS>
          <AutoAssignPort>False</AutoAssignPort>
          <DevelopmentServerPort></DevelopmentServerPort>
          <DevelopmentServerVPath>/</DevelopmentServerVPath>
          **<IISUrl>http://localhost/myWebSiteAppSample</IISUrl>**
          <NTLMAuthentication>False</NTLMAuthentication>
          <UseCustomServer>False</UseCustomServer>
          <CustomServerUrl>
          </CustomServerUrl>
          <SaveServerSettingsInUserFile>False</SaveServerSettingsInUserFile>
        </WebProjectProperties>
      </FlavorProperties>
    </VisualStudio>

And that is. Now you can load your project normally.

17
votes

The problem would be your project setup to be executed in the local IIS and the URL specified not exist.

There are options you can do to fix the problem.

Option 1 : (Use IIS Express)

1.) Open you web project .csproj file as XAML or in notepad.

2.) Find these properties and set according to your preferences.

UseIIS = false

UseIISExpress = true

and that's it.

Option 2 : (Use local IIS)

Follow the option 1 steps but change the following properties.

UseIIS = true

IISUrl = https://localhost

UseIISExpress = false

9
votes

The issue can be fixed by deleting the folder named .vs in the project directory.

This solves the problem because while opening the project after deleting the .vs file, it creates the same folder with subfolder config and folder with project name.

The config folder applicationhost contains the necessary settings required to run the project successfully.

6
votes

I just went to the directory named in the error and renamed the applicationhost.config and restarted and VS created a new file and ran fine.

3
votes
  • Tried several approaches mentioned in the answers, but what finally worked for me was swapping the <IISUrl> of .csproj with <CustomServerUrl>.

Edit :

  • The above didn't solve the root cause of the issue for me. However, If you've done a windows update recently, perhaps it might be the reason that's causing the issue. Try executing netsh http add iplisten 0.0.0.0 and see whether it solves the issue.

Hope these would help someone still looking for a way.

1
votes

I don't know why, by my applicationhost.config file was completely missing from my C:\Users\Administrator\Documents\IISExpress\config\ folder.

Copy/pasting C:\inetpub\history\applicationhost.config into that folder seemed to fix the problem for me.

Got the idea from here.

1
votes
  1. Turn on windows features "Internet Information Services" in control panel.
  2. Open ".csproj" file and find
  3. Modify this line based on your requirements. http://localhost:777/
  4. Open the project/solution now
  5. If failed to load again, just right click the solution and select "Reload Project".
1
votes

I know this is probably a rare occurrence, but figured I'd put it here:

My csproj file was set to "read only" (Don't ask me how I managed that), but after I turned off "read only" access, everything was fine. (VS2017)

1
votes

Not the exact same error, but I was lead to this answer since the first half of the error matched. Your applicationhost.config file may simply be read-only. Taking that off solved the error for me. That error calls out the file specifically though, so you should be able to find it easily.

1
votes

I had to somewhat combine some of the above answers. My solution was to edit (not delete) the file .vs\config\applicationhost.config

There is a section for the bindings of the site, simply change from localhost to whatever you desire to run it under. Note that the port numbers are in front of the server name.

applicationhost.config bindings section

0
votes

I was facing the same issue because of my network password changed.I changed my NetExtendor login password but I have to login in my laptop with old password.

Try these steps to fix this issue:

log into the Computer with whatever password works log into vpn with whatever password works ctl-alt-del to lock the pc then use the new password to unlock it

It worked for me :-)

Thanks!

0
votes

So here are the steps to fix it:

  1. Go where your .csproj file is. This is usually one directory below the solution (.sln)
  2. Right click and open with a text editor (notepad)
  3. Find IISUrl tag and replace its content for http://localhost:(YourPortNumber)
  4. Save and reload your project!
0
votes

My issue was with Windows 10 Defender. I had given IIS permission in the past, but seems like it is now ignoring it. Will look into it later, but for now I disabled controlled folder access and it worked.

0
votes

I wanted open an exiting project of Visual Studio 2017 in VS 2019 and encountered with the same issue. I find its a version related problem. The solution is: Create a new project in the newer VS and copy the codes from the older VS.

0
votes

Try decrypting the applicationhost.config file. That worked for me.