httpclient PostAsJsonAsync (n)消息后错误(端口耗尽?)

我有一个在Azure中运行的控制台应用程序(webjob)，它调用在Azure中运行的API。控制台应用程序从csv文件发布消息。当我从本地(windows 10)机器上运行控制台应用程序(在azure中运行api)时，它按预期工作(没有错误)。当我在Azure中运行控制台应用程序(在Azure中运行api)时，它处理大约980条消息，然后开始报告错误

错误:

• "发送请求时发生错误"
• "无法连接到远程服务器"

我相信，由于某种原因，当控制台应用程序在Azure中运行时，它正在耗尽端口，但我不知道如何解决这个问题。我的文件有50,000行，但如前所述，在问题出现之前只有大约980行。在另一端，api将接收到的消息发送到sql数据库和azure事件中心。一旦PostAsJsonAsync完成，我如何强制应用程序释放端口?如何检查端口是否已释放，或者如何检查端口是否可用?如果你知道我可能得到这些错误的任何其他原因，请帮助。

下面是我的代码:

public async Task<string> PostMessageToAPI(string aMsg)
{
    HttpResponseMessage response = null;
    string strResponse = "";    
    try
    {
        using (var client = new HttpClient())
        {
            client.SetBearerToken("access token here");
            client.BaseAddress = new Uri("MyBaseUrl.com");
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            using (response =  await client.PostAsJsonAsync("my/url/goes/here", anEvent.ToLower()))
            {
                if (response != null)
                {
                    if (response.StatusCode != HttpStatusCode.OK)
                    {
                        throw new HttpRequestException(response.ReasonPhrase);
                    }
                    else
                    {
                        return await response.Content.ReadAsStringAsync();
                    }
                }
            }
        }
    }
    catch (HttpRequestException ex)
    {       
        //  exception message states: "An error occurred while sending the request"
    }   
    return strResponse;           
}

Visual Studio 2015 update 3
• . net 4.5.1
• Azure控制台应用程序计划:基本1小
• Azure API应用程序计划:基本1小

public class MyClass()
{
private HttpClient client = null;
public MyClass(){
    client = new HttpClient();
    client.SetBearerToken("access token here");
    client.BaseAddress = new Uri("MyBaseUrl.com");
    client.DefaultRequestHeaders.Accept.Clear();
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
public async Task<string> PostMessageToAPI(string aMsg)
{
    HttpResponseMessage response = null;
    string strResponse = "";    
    try
    {
        using (var response =  await client.PostAsync("my/url/goes/here", new StringContent(aMsg, Encoding.UTF8, "application/json")))
        {
            if (response != null)
            {
                if (response.StatusCode != HttpStatusCode.OK)
                {
                    throw new HttpRequestException(response.ReasonPhrase);
                }
                else
                {
                    return await response.Content.ReadAsStringAsync();
                }
            }
        }
    }
    catch (HttpRequestException ex)
    {       
        //  exception message states: "An error occurred while sending the request"
    }   
    return strResponse;           
}
}