IIS error Unable to start debugging on the webserver

Question

I want to run my application from IIS on my local machine  I created the virtual directory and added the application to it and in the properties folder of the application I checked the radio button  Use Local IIS Webserver   I then started running my application but I m getting the following error   Unable to start debugging on the webserver see help for common configuration errors Running the webpage outside of the debugger may provide further information  Make sure the server in operating correctly Verify there are no syntax errors in web config by doing a debug Start Without Debugging You may also want to refer to the ASP NET and ATL Server debugging topic in the online documentation   How do I get rid of this error  I m using Visual Studio 2010 on Windows 7 and IIS 7 5

User · Answer

Just one of the 10 sites configured on my Local IIS was giving this error, so I had a feeling that it wasn't anything from the other answers that were machine-wide things, like Turning Windows Features On or Off, or running VS2015 as admin (the other 9 sites worked ok, in the same VS).

The specific error for me was:

Unable to start debugging on the webserver. Operation not supported. Unknown error:0x80004005

The problem turned out to be the web config having a URL Rewrite rule to rewrite HTTP -> HTTPS. Commenting this out resolved the problem

TL;DR - try disabling all your web.config URL rewrite rules, if you have them (then add them back in gradually, if it helps)

User · Answer

Just an update as I hit this issue and all of the settings in both Visual Studio and IIS seemed to be correct   What actually worked for me was simply running Visual Studio as an administrator - I m guessing that there is a permission that needs to be set somewhere  but I have no idea what or where   Also a point to note is that I configured all my websites to use the DefaultAppPool in IIS which at the time was ASP NET V2  then installed  NET 4 and the DefaultAppPool was converted to  NET4 so none of the sites would compile  that caused me a small amount of swearing   Hope that helps someone

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Use Microsoft Web Platform Installer to install IIS ASP NET 4 5    Found the solution here    https   msdn microsoft com en-us library dwesw3ee aspx https   msdn microsoft com en-us library mt621540 aspx BKMK deploy asp net

User · Answer

In my case it was the lack of debug  true  in web config  system web -  compilation    example    lt system web gt      lt compilation debug  true  targetFramework  4 5 2    gt           lt  system web gt

User · Answer

For who has same issue on VS Professional 2019  I Installed Xamarin bundle and after that this IIS error starts  I have tried all solutions above without any luck  What I did to fix it is      From Visual Studio Installer check Development time IIS support from web  amp  Cloud - ASP NET and web development   Restart IIS  Open solution - Issue fixed

User · Answer

Just ran into this problem myself and it turned out to be that my site in IIS was set up to use anonymous authentication with a specific network account   I had been forced to reset the password on that account  and so IIS was failing because it was using the old one   Once I updated the site with the new password  or even better  changed it to use Network Service instead   all worked again

User · Answer

Thanks for all the answers but none of them worked for me  Although some of them gave me some ideas on what services and stuff that needs to be running to be able  turn on  the debugging of my web app again    Ensure that ASP Net registered properly with IIS and running  To register it follow  Rahul Tripathi instructions then go to Search   type services msc and make sure that ASP Net State Service is running  As  Morvael suggested  always run your VS in admin mode  Check if the app pool where your web app resides is started  Ensure that the IIS server itself is running  this what solved the problem for me    I still haven t figured out what is the reason why my IIS stopped  It was working fine yesterday then today it s not  Anyways  I hope this mini checklist helps somebody else  Cheers

User · Answer

Do you use or have IIS Rewrite installed on your machine   I have a similar problem on my machine but to get round it  I have web config open as the current page in VS and press f5   I then have to navigate to the page to debug   It seems to work for me

User · Answer

In my case it looks like Chrome locking some resources  preventing from debugger to attach  After I closing Chrome  I able to attach again

User · Answer

I m running Windows 10 Professional with Visual Studio 2017 and none of the options above worked for me   What fixed it for me was adding  Windows Process Activation Service    Start   Type turn windows Features On or Off   Make sure  Windows Process Activation Service  is checked   Hope it helps someone

User · Answer

Check the Physical Path    In my case  I had changed it by mistake   In IIS  click on your website  then go to Basic Settings     Check the path  and check the credentials  Enter the new credentials if needed     To change the path  you can go to Visual Studio  Project - Properties  and recreate the Virtual Directory     If asked to remap   click Yes

User · Answer

I went through every answer here and nothing worked   My situation was IIS and had a self signed certificate created a week ago   Worked fine for a week and all of a sudden I started getting the 403 s   Finally I closed Visual Studio  went into IIS and deleted the virtual directory  went back in visual studio and created a virtual directory from the project web settings and everything started working again   The self cert had a year expiration date so I m not sure why it just stopped working but this got me back up

User · Answer

Follow my steps      Open your web config file   See your  staticContent  tag  Delete or commend unwanted setting tag ex  -   lt  mimeMap fileExtension   woff  mimeType  application x-font-woff

User · Answer

I didn t see this answer on this thread or the  possible duplicated  question here    I fixed the issue by     Opening the Task Manager  ctrl alt del  Under the Processes tab  End the task of IIS Worker Process  This may now be listed as Microsoft IIS Worker Process or something similar   You may have to click More details at the bottom if you don t see all of the processes  Then going to the Services tab  Stop the IISADMIN service and the start it up again     Run the program and that should hopefully fix it  Happy Coding and Debugging

User · Answer

Make sure that you etc file in C  Windows System32 drivers does not has any other applications with the same name as the one you are getting an error on   I had a Hadoop sandbox configured with the name  localhost  which was the same as my Visual Studio project which was getting the  Cannot start debugging on web server  error   Remove those lines and your project should start debugging

User · Answer

I had the same issue  The problem was I haven t Framework 4 installed while I had already Framework 4 5  So MIME type ASPX could not be realized without ISAPI 4 0   To sort it  I could either uninstalled 4 5 first and add 4 0 then which made trouble or adding specific files to ISAPI restriction and ISAPI filter in the IIS root manually   I needed to grab aspnet filter dll and aspnet isapi dll located in both C  Windows Microsoft NET Framework  and C  Windows Microsoft NET Framework64    Having added those files  all would be good

User · Answer

Check your web config  if there are problems  you may get this error  I had a HTTP to HTTPS redirect in the web config but the application was set to launch as http   To fix  Local IIS     Configure a https binding for your application in IIS  Right click the web project then Properties   Web  Under Servers  set the URL to your https URL

User · Answer

If you are using HTTPS on localhost  odds are you created a self signed certificate  These have a tendency to expiry on the same day they are created  so you could have to recreate a certificate and add it to the binding of your locally hosted site

User · Answer

go to Search   type services msc and make sure that ASP Net State Service is running

User · Answer

There may be many reasons for the above problem   You need to check this - Unable to Start Debugging on the Web Server  On a side note - Go to IIS and check that the App Pool you are using is started   Try this from your command line -  cd  windir  Microsoft NET Framework v4 0 30319 aspnet regiis exe -i

User · Answer

It always happens to me after my network password changes  Open IIS    choose the Application pool    Advanced settings    Application Pool Identity    Set Credentials    set username and the new password   also    make sure the status of the application pool is  Started   Restart IIS  via IIS manager or open cmd as administrator and run the command iisreset

User · Answer

In my case this problem happened after my windows 10 updated to the latest version  -I have tried most of above solutions but not helped me  -I also checked event viewer to see what error happened   this is the error related to iis was happened but not found any solution on internet about it after a lot of search     The Module DLL  C  WINDOWS System32 inetsrv cgi dll  could not be loaded due to a configuration problem  The current configuration only supports loading images built for a AMD64 processor architecture  The data field contains the error number  To learn more about this issue  including how to troubleshooting this kind of processor architecture mismatch error  see http   go microsoft com fwlink  LinkId 29349      The way i solve this problem is changing Enable 32-Bit Applications value to True  by right clicking on DefaultAppPool in IIS Manager and select Advanced Settings

User · Answer

The best answer online is at here  I tried the fifth method    Right click on your project in VS2005 or VS2008 or VS2010 Click on Properties Click on Web tab Under Servers  click on the radio button Use Visual Studio Development Server Check Auto Assign Port radio button Uncheck NTLM Authentication and Enable Edit and Continue   Now run your application it will work for you

User · Answer

Building on the answer from  MiscellaneousUser  in my case it was the enabling of HSTS that I had done to force the website to use HTTPS instead of HTTP    To solve the problem I had to disabled HSTS in the applicationHost config file  which is usally found here  C  Windows System32 inetsrv Config applicationHost config  The relevant line of the file is this - I just changed enabled from true to false    lt hsts enabled  false  max-age  31536000  includeSubDomains  true  redirectHttpToHttps  true    gt    Obvious you need to consider the security impact of disabling HSTS  In my case this is my development PC so I only had HSTS turned on to simulate what production does

User · Answer

reset your iis in  Developer Command Prompt for  your visual studio version    type iisreset in that command prompt  amp  hit enter  it ll reset iis automatically

User · Answer

I ve faced this problem  then I found out that i gotta run Visual Studio as admin in order to debug the project   Hope it helps

User · Answer

None of the other solutions worked for me  I resolved this issue by using the commands below   For 32 bit machine   C  WINDOWS Microsoft NET Framework v4 0 30319 gt aspnet regiis    i   For 64 bit machine   C  WINDOWS Microsoft NET Framework64 v4 0 30319 gt aspnet regiis    i   The issue is because the web config file is not installed correctly

User · Answer

If you are using active directory login u need to check password and username

User · Answer

in my case  the DefaultAppPool was stopped  I edited the Advanced Settings and set the value of Identity as LocalSystem  after that I start the DefaultAppPool

User · Answer

I tried everything on here and finally discovered that it was the  setup in my web config  I removed that section and it worked fine  I will go back and troubleshoot later as to why it was busted   Edit  I removed the statusCode  quot 503 quot  because of an issue with the App Offline htm file and the way in which the errors were configured  I ve removed the line below  it isn t needed locally   and everything is working perfectly   lt remove statusCode  quot 503 quot   gt

User · Answer

In my case this folder was missing      C  Windows Microsoft NET Framework v4 0 30319 Temporary ASP NET Files   Adding that folder and the necessary permissions solved it for me

User · Answer

Project Properties   Web   Servers  Change Local ISS   ISS Express  Change ISS

User · Answer

Just to add in my 2 cents  Recently I installed docker for another project and this was causing a project running on IIS Express to generate the error    The specified port is in use     To solve this I did a few things  but namely I executed this command  netsh http add iplisten ipaddress     This commands breaks down sites running on IIS Local  so if you executed this command you can make your IIS Local sites working again by executing the following which undoes the previous command  netsh http delete iplisten ipaddress

User · Answer

I resolved this issue  In my case my application pool was stopped  After little bit of Googling i found out that application pool was running under some user identity and password was changed for that user  After updating password it starts working fine

User · Answer

If you can check your logs you should be able to get an error status and substatus   Logs are usually located at  SystemDrive  inetpub logs LogFiles  I just had to face a similar problem  looking at the log i ve found   2018-11-12 10 09 22   1 DEBUG  PPD debugattach aspx - 80 -   1 - - 403 4 5 0   Here the status is 403 and substatus is 4  this table https   support microsoft com en-ca help 943891 the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0 provided the  knowledge to fix the problem  403 4 is in fact SSL Required  once i ve changed the project URL in Visual Studio from http to https  Project properties -  Web -  Server -  Project URL  the problem disappeared   I ve described my fix only to clarify the steps involved in fixing the issue  read all the answer and not just from  once i ve changed the project URL     and follow your logs   Good luck

User · Answer

Just to add  I had this issue  and fixed by disabling the Load User Profile option  unsure of any side effects   This is found through Advanced Settings for the Application Pool     This then made it work for me

User · Answer

I ve seen alot of different solutions for this  iisreset did the trick for me   Just open an elevated command prompt and type   iisreset

User · Answer

Just had the same issue after VS crashed and Rahul s comment regarding the application pool pointed me in the right direction  In my case recycling the app pool did the trick  IIS Manager    App Pools    right click on ap in question and recycle

User · Answer

This could be a case of wrong windows user credentials    This issue happens quite often after importing existing IIS projects that require a Windows username and password configured   To solve this  make sure both the Application pool app  the website  and the website app are configured to work with your machine s credentials    On the IIS server node  select the pool-application app website and choose Advanced Settings  Check if the value of Physical Path Credentials is correct  fix it if not       On the IIS server node  select the pool-application app website and choose Basic Settings  Click on  Test Settings  and validate that the credentials are correct

User · Answer

There are multiple solution of this problem  in my case I changed my machine s password but forget to change it in the process model identity of Advance setting of that Application pool   Later IISRESET did the trick for me

User · Answer

I edited the solution file and changed localhost to my ip address   Before that I had added IIS IUSRS with full control in the project directory   I can now debug

[asp.net] IIS error, Unable to start debugging on the webserver

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