Ran into this this issue while hacking on a problem with my Dad, Jim Killeen. (Side note: looking at tech stuff with my Dad remains one of my great joys in life.)

Context

My Dad is building a client-side Blazor app, because he’s more hip with technology than I am.

Problem

When publishing / deploying the app, upon it attempting to start up and communicate with a Web API, we see an error of HTTP Error 500.30 - ANCM In-Process Start Failure.

Solution

This is caused because the client-side web app cannot communicate securely with the Web API, which is fair. We want to make sure there’s trust there. So to get that trust in place, we’ll need to generate a self-signed certificate and set up the IdentityServer configuration to use it.

Creating the Self-Signed Certificate

Modify the variables in the below powershell and then execute it (save as a .ps1 and run it or enter it line by line into a console) to create a self-signed certificate.

$AzureWebsiteName = "mywebsite.azurewebsites.net"
$CertPassword = "MyPassword!123" # Pick a better password than this. Please.
$PfxOutputLocation = "C:\temp\cert.pfx" # Folder must already exist

#### You shouldn't need to modify anything below this line.

$cert = New-SelfSignedCertificate -certstorelocation cert:\localmachine\my -dnsname $AzureWebsiteName

$pwd = ConvertTo-SecureString -String $CertPassword -Force -AsPlainText

$path = 'cert:\localMachine\my\' + $cert.thumbprint 
Export-PfxCertificate -cert $path -FilePath $PfxOutputLocation -Password $pwd

At this point, you should have a .pfx file with the appropriate password that you specified.

Uploading the Certificate into Azure

Open the Azure portal and navigate to your web site
On the left-hand settings menu, select TLS/SSL Settings

In the top menu, select Private Key Certificates (.pfx)

From the sub-menu, select upload.

Select the cert location and enter the password you previously chose for it.

Upload the cert. You will now see it in the certificates list.

Add the Certificate Thumbprint to your Azure Web Site Configuration

Next, we need to ensure that Azure can access the certificate you’ve provided. There’s a configuration setting for that.

In your certificates list, you should see your newly uploaded certificate
Click on the certificate and copy its thumbprint
Go to the Configuration variables for your web application
Create a variable called WEBSITE_LOAD_CERTIFICATES and set its value to the thumprint you copied
Save the settings.

Updating the IdentityServer Settings

Okay, so there’s one more part to go. In your appSettings.json or wherever that is being transformed, add or edit IdentityServer configuration as follows:

"IdentityServer": {
  "Key": {
    "Type": "Store",
    "StoreName": "My",
    "StoreLocation": "CurrentUser",
    "Name": "CN=MyApplication"
  }
}

Replacing CN=MyApplication with your site name, e.g. CN=mywebsite.azurewebsites.net.

Give it a spin!

Open up the application in Azure, annnd success. :)

I hope this helps someone out. Happy coding!

Solved: Blazor IdentityServer 500.30 Error (ANCM Issue)