C# HttpClient.SendAsync 导致错误，无法发送具有此谓词类型的内容正文

问：

我收到错误，无法发送带有此谓词类型的内容正文。我正在从 C# VSTO 桌面应用程序调用 GET 终结点。我做错了什么。

public static string GetCentralPath(LicenseMachineValidateRequestDTO licenseMachine)
{
    using (var client = new HttpClient())
    {
        client.DefaultRequestHeaders.Authorization =    new AuthenticationHeaderValue("Bearer", Properties.Settings.Default.Properties["JWT"].DefaultValue.ToString());
        var request = new HttpRequestMessage
        {
            Method = HttpMethod.Get,
            RequestUri = new Uri($"{Constants.URL.APIBase}licensemachine/GetCentralPath"),
            Content = new StringContent(JsonConvert.SerializeObject(licenseMachine), Encoding.UTF8, "application/json"),
        };
        
        using (HttpResponseMessage response = client.SendAsync(request).GetAwaiter().GetResult()) // Causing ERROR
        {
            var result = GetStringResultFromHttpResponseMessage(response, true);
            if (string.IsNullOrEmpty(result))
                return null;
            return JsonConvert.DeserializeObject<string>(result);
        }
    }
}

端点如下所示：

[HttpGet("GetCentralPath")]
public async Task<IActionResult> GetCentralPath(LicenseMachineValidateRequestDTO dto)
{
    // Some code
}