老师这是浏览器端报的错500，后端代码排查。我没有找到错误。您帮我在看看。

consumer.py代码是：

import json
from channels.generic.websocket import AsyncWebsocketConsumer
class MessagesConsumer(AsyncWebsocketConsumer):
    """处理私信应用中WebSocket请求"""
     async def connect(self):
         if self.scope['user'].is_anonymous:
        # 未登录的用户拒绝连接
         await self.close()
         else:
           await self.channel_layer.group_add(self.scope['user'].username, self.channel_name)
          await self.accept()
    async def receive(self, text_data=None, bytes_data=None):
        """接收私信"""
        await self.send(text_data=json.dumps(text_data))
    async def disconnect(self, code):
        """离开聊天组"""
        await self.channel_layer.group_discard(self.scope['user'].username, self.channel_name)

urls.py代码是：

from django.urls import path
from zanhu.messager import views
app_name = 'messager'
urlpatterns = [
    path('', views.MessagesListView.as_view(), name='messages_list'),
    path('send-message/', views.send_message, name='send_message'),
    path('<username>/', views.ConversationListView.as_view(),name='conversation_detail'),
] 
    

views.py代码是：

@login_required
@ajax_required
@require_http_methods(["POST"])
def send_message(request):
    """发送消息，AJAX POST请求"""
    sender = request.user
    recipient_username = request.POST['to']
    recipient = get_user_model().objects.get(username=recipient_username)
    message = request.POST['message']
    if len(message.strip()) != 0 and sender != recipient:
        msg = Message.objects.create(
            sender=sender,
            recipient=recipient,
            message=message
        )
        channel_layer = get_channel_layer()
        payload = {
            'type': 'receive',
            'message': render_to_string('messager/single_message.html', {"message": msg}),
            'sender': sender.username
        }
        # group_send(group: 所在组-接收者的username, message: 消息内容)
        async_to_sync(channel_layer.group_send)(recipient.username, payload)
        return render(request, 'messager/single_message.html', {'message': msg})
    return HttpResponse()