Unable to connect to ASP.Net Development Server issue

Try commenting out the following line, if it exists, in your hosts file (`%windir%\System32\drivers\etc\hosts`):

::1 localhost

This worked for me using Visual Studio 2008 SP1 on Vista Ultimate x64 SP2.

Under project settings, try specifying a different port like 64773 for example. I have encountered this issue many times and it has always worked for me.

It cause the already that project port server is running in the current thread. You need to end process using task manager.

Follow below step:

1. Pres Ctrl+Alt+Delete (Task Manager)

2. find the asp.net server like
WebDev.WebServer40.exe for VS2010
and press end process.

3. Now u continue with vs2010 run
button

--Problem Definition

------ whenever we debug our project (either by pressing ctrl+f5 or only f5) the first .exe which is called by VS is called WebDev.WebServer.EXE which got corrupted may be n number of reasons



--Solution

------ We need to replace this file

------Step 1 ---

go location C:\Program Files\Common Files\Microsoft Shared\DevServer\9.0

You will find this file

-------Step 2 ---

download WebDev.WebServer.rar file from

[To see links please register here]

-------Step 3 ---

NOTE : You will need password for extraction this downloaded .rar file

Password : optimusprime

------ Step 4 ---

Copy the downloaded WebDev.WebServer.EXE file and replace in this below path

"C:\Program Files\Common Files\Microsoft Shared\DevServer\9.0
"

--------step 5------

run the program

I went to the project file and changed the development server port to 1504. Well 1504 worked on another project for me, so I went with that. Hope this helps.

I got this problem a couple of times and done different things to fix it. When I got it this time all I did to stop getting "unable to connect to asp..." error, was rename the web app folder directory from `xpCal` to `xpCal2.` I also tried moving the web app directory to a different directory from `C:users\<me>\desktop\` to `C:\users\<me>\desktop\new folder` and it also worked.

I don't know why it worked, does VS 2010 keep information about web apps seperate from web apps folder.

Go to Run >> type >> cmd >> type
taskkill /IM webdev.webserver20.exe
and then try to re run the program

In my case I was using Windows 8 and Windows Firewall was blocking WebDev.WebServer.EXE

So I went to the settings of Windows Firewall > Allow an app through Windows Firewall > Add new
and browse to C:\Program Files (x86)\Common Files\Microsoft Shared\DevServer\11.0
Then select WebDev.WebServer to allow.

In my case, when I had the ASP.NET Development Server crash, one thing that worked was to change the port for the project.

I suspect what happened was when the web server crashed it did not release a lock on the port. Even though it was not running in Task Manager, something was blocking a new instance of the web server from starting again on the original port. Changing the port was a decent enough work around. I could have rebooted, but who has time for that, right?

Details: Windows 7 x64, VS2010, .NET Framework 4.0, ASP.NET web site using the built in web server to VS2010.

BTW, I would be a little cautious with replacing the `WebDev.WebServerServer.EXE` as suggested in other posts. If that file has been corrupted then you have bigger problems with your OS.

For some poor souls out there starting using TypeMock on ASP.NET unit tests like me, you need to disable it in Visual Studio to avoid this error: In Tools->Add-in Manager, untick the boxes for TypeMock Isolator. I guess you need to switch this back on for your unit tests.