Dotnet to Dotnet call on Ubuntu failing with SSL connection error

Question

I have two projects that I'm running with dotnet 6 on Ubuntu, one is the UI and the other is the API, when the UI makes a call to the API, it returns an exception that is

Exception has occurred: CLR/System.Net.Http.HttpRequestException
Exception thrown: 'System.Net.Http.HttpRequestException' in System.Private.CoreLib.dll: 'The SSL connection could not be established, see inner exception.'
 Inner exceptions found, see $exception in variables window for more details.
 Innermost exception     System.Security.Authentication.AuthenticationException : The remote certificate is invalid because of errors in the certificate chain: UntrustedRoot

When I run dotnet dev-certs https --check it returns

A valid certificate was found: A09013A82738B7690B99C4CDECEA868CBA73CB4D - CN=localhost - Valid from 2022-08-25 20:00:24Z to 2023-08-25 20:00:24Z - IsHttpsDevelopmentCertificate: true - IsExportable: true

I used the respective script for Ubuntu from this repository and the UI and API both show as https in the browser afterwards. As a means of bypassing the check for ssl, I placed this in the Program.cs for both the UI and API

public class CustomHttpMessageHandlerBuilder : HttpMessageHandlerBuilder
{
    public override string Name { get; set; }
    public override HttpMessageHandler PrimaryHandler { get; set; }
    public override IList<DelegatingHandler> AdditionalHandlers => new List<DelegatingHandler>();
    // Our custom builder doesn't care about any of the above.
    public override HttpMessageHandler Build()
    {
        return new HttpClientHandler
        {
            // Our custom settings
            

            ServerCertificateCustomValidationCallback = delegate {return true;}
        };
    }
}

and above it

builder.Services.AddTransient<HttpMessageHandlerBuilder, CustomHttpMessageHandlerBuilder>();

I also tried the option

ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator

But none of it has any effect, I'd rather not mess with the code too much but if it's a matter of a few lines in the Program.cs that would be a viable alternative but preferably I'd like to figure out why my UI and API projects cannot communicate properly.

Answer 1

Had similar error.
Environment: Ubuntu 22.04, dotnet 6.
In my case, I created and trusted cert as indicated in microsoft docs:

• Created developer certificate via dotnet dev-certs...
• Trusted cert as indicated here
• When client tried to communicate with api via httpclient (from factory), would get "...UntrustedRoot..." exception
• Workaround: Added this to the http client factory configuration, in Program.cs , client app only:

...
.ConfigurePrimaryHttpMessageHandler(serviceProvider => new HttpClientHandler()  
{  
    ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator  
})
...