Microsoft Bot Framework无法使用Azure中运行的聊天机器人服务中的图像进行回复

Question

我在Azure中运行了一个LUIS bot服务。当我尝试使用图像回复用户（通过Microsoft团队）时，它会失败。我可以使用bot模拟器和图像的本地路径在本地运行相同的代码，并且它可以工作。代码如下。失败的代码行是这一行：

await connector.Conversations.ReplyToActivityAsync（reply）;

    public async Task ChitChatResult(IDialogContext context, LuisResult result)
    {
        ConnectorClient connector = new ConnectorClient(new Uri(context.Activity.ServiceUrl));            
        var activity = new Activity(); 
        Activity reply = ((Activity)context.Activity).CreateReply();
        reply.Attachments = new List<Attachment>();
        reply.Attachments.Add(new Attachment()
        {
            ContentType = "image/png",
            Name = "ShutIt.PNG",
            //ContentUrl = $"C:\\Users\\casieo\\ShutIt.png"//when I debug locally in the bot emulator with this ContentUrl, the image is returned in the reply
            ContentUrl = $"https://xxx.scm.azurewebsites.net/dev/api/files/wwwroot/images/ShutIt.PNG"

        });

        await connector.Conversations.ReplyToActivityAsync(reply);           
        await context.PostAsync($"Just kidding.  But seriously, I'm not good at chit chat, but if you ask me a specific question, I should be able to help.  For ideas about what I understand, reply back with 'what can i say?'");

}

如果我在ConnectorClient对象中包含MicrosoftAppId和MicrosoftAppPassword，则没有区别。可以使用我包含的ContentUrl在浏览器中访问该图像。

有什么想法吗？