HTTPClient and JWT Authentication in C#

I'm having a hard time trying to use authorization in C# Winforms. My purpose is to access the API. I already get the access token but when I try to pass it to the header, it returns an error:

HTTP error 400.

My code:

using (var httpClient = new HttpClient())
{
    var url = @"https://acerportal.com/v1/414232363/status/device/";
    httpClient.BaseAddress = new Uri(url);
    httpClient.DefaultRequestHeaders.Accept.Clear();
    httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", accessToken);

    var response = await httpClient.GetStringAsync(url);
    string checkResult = response.ToString();
    MessageBox.Show(checkResult);
}