Angular App, C# API, Windows Authentication

I would like to use the windows credentials for domain users to access a C# REST Api. The web app is a very simple Angular 12 app that currently just needs to display the version of the REST Api. I have a endpoint called /api/version that looks like this:

    [AllowAnonymous]
    [HttpGet]
    public IActionResult Get()
    {
        Assembly assembly = Assembly.GetExecutingAssembly();
        FileVersionInfo fileVersionInfo = FileVersionInfo.GetVersionInfo(assembly.Location);

        var versionInfo = new[]
        {
            new
            {
                company = fileVersionInfo.CompanyName,
                product = fileVersionInfo.ProductName,
                version = fileVersionInfo.FileVersion
            }
        };

        return Ok(versionInfo);
    }

calling http://test:5050/api/version in the browser displays the version info without any problems. If I remove the [AllowAnonymous] I get prompted to logon (my PC is not in the domain) - when I do this all good. This is what I want - all good!

My problem is if I access the endpoint in Angular:

    getVersion(): void {
        this._httpService.getVersion('/api/version').subscribe(
            (data) => {
                this.homeForm.patchValue(data)
            },
            (err) => console.error(err),
            () => console.log('done loading getting version info')
        )
    }

the httpService is very simple:

 getVersion(url: string): Observable<any> {
           return this.http.get(url)
    }
}

I have a button in the HTML that calls getVersion() -> when I press it I get get prompted to logon... I don't really understand why?

I am using all the newest versions of everything -> Visual Studio 2022, Angular 12 (that's still new, right 😊), IIS 10