CODEWITHSUNDEEP
asp.net-corevisual-studio-2017iis-express
spottedmahn
spottedmahn

Reputation: 15981

Can't Start IIS Express: An error occurred attempting to determine the process id

When I try to start my ASP.Net Core 1.1 app, I'm receiving the following error:

An error occurred attempting to determine the process id of Blah.exe which is hosting your application. An error occurred while sending the request.

I changed the applicationUrl port number from 44300 to 44301 in `launchSettings.json' and I was able to get it to start.

{
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "https://localhost:44301/",
      "sslPort": 44301
    }
}

Why did changing the port # make it work? Where can I look to figure out why it wouldn't startup?

I ran TCPViewer and I don't see 44300 in use.

Upvotes: 0

Views: 6025

Answers (1)

spottedmahn
spottedmahn

Reputation: 15981

Uninstall and re-install of IIS Express fixed it.

Turns out port 44300 wasn't bound to my IIS Express cert. Bill Hiebert figured it out as documented in this developer community issue.

When I ran netsh http show sslcert, port 44300 wasn't listed. I uninstalled and re-installed IIS Express and now it is listed.

SSL Certificate bindings: 
------------------------- 

IP:port                      : 0.0.0.0:44300
Certificate Hash             : somevalue
Application ID               : {someid}
Certificate Store Name       : MY
Verify Client Certificate Revocation : Enabled
Verify Revocation Using Cached Client Certificate Only : Disabled
Usage Check                  : Enabled
Revocation Freshness Time    : 0
URL Retrieval Timeout        : 0
Ctl Identifier               : (null)
Ctl Store Name               : (null)
DS Mapper Usage              : Disabled
Negotiate Client Certificate : Disabled
Reject Connections           : Disabled
Disable HTTP2                : Not Set

Upvotes: 3

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