looking for specific api call using titanium web proxy in my c# app doesn't work but when i use fiddler classic it works

I'm trying to intercept HTTP/HTTPS traffic from a Windows application using Titanium Web Proxy in my C# app.

My C# app sets up an explicit proxy on port 8888 and captures most HTTPS requests just fine (e.g., from login.live.com, events.data.microsoft.com, etc.). However, traffic to what i need is never seen in my proxy.

What's confusing is: If I use Fiddler Classic, I can see the traffic to the api. So I know the traffic exists and isn't encrypted in a way that makes interception impossible.

            proxyServer = new ProxyServer();

            proxyServer.CertificateManager.CreateRootCertificate();
            proxyServer.CertificateManager.TrustRootCertificateAsAdmin();
            proxyServer.CertificateManager.EnsureRootCertificate();
            proxyServer.EnableConnectionPool = true;


            var explicitEndPoint = new ExplicitProxyEndPoint(System.Net.IPAddress.Any, 8888, true);

            proxyServer.AddEndPoint(explicitEndPoint);
            proxyServer.Start();

            proxyServer.SetAsSystemHttpProxy(explicitEndPoint);
            proxyServer.SetAsSystemHttpsProxy(explicitEndPoint);

            proxyServer.BeforeRequest += OnRequest;
            proxyServer.BeforeResponse += OnResponse;
    ```

    private static async Task OnRequest(object sender, SessionEventArgs e)
    {
        Console.WriteLine($"[Request] {e.HttpClient.Request.Url}");
        await Task.CompletedTask;
    }


    private static async Task OnResponse(object sender, SessionEventArgs e)
    {
        Console.WriteLine($"[Response] {e.HttpClient.Request.Url}");
        await Task.CompletedTask;
    }