Azure App Services至AI Search私网部署报错InvalidOperationException求助

• Azure App Services
• Azure AI Search

通过Azure AI Studio部署sample-app-aoai-chatGPT应用，公网环境运行正常，但建立Azure App Services至Azure AI Search的私网连接时，应用失败并提示：

检测到无效的Azure认知搜索配置：获取ACS索引的调用失败。请检查是否使用了正确的索引、实例和API密钥。

• Azure App Services已集成到虚拟网络的子网中
• Azure AI Search在同一虚拟网络的另一个子网配置了专用终结点
• Azure AI Search已禁用公网访问

• 通过Kudu和nslookup确认DNS解析到私网IP地址
• 启用Azure AI Search公网访问后，应用恢复正常
• 向Azure AI Search专用终结点发起REST API调用可返回预期结果
• Azure App Services至Azure AI服务专用终结点的出站访问正常

2024-02-05T16:18:53.465043284Z: [ERROR]  [2024-02-05 16:18:53 +0000] [79] [ERROR] Error handling request
2024-02-05T16:18:53.465111184Z: [ERROR]  Traceback (most recent call last):
2024-02-05T16:18:53.465117884Z: [ERROR]    File "/tmp/8dc1e90f6f97d9f/app.py", line 398, in stream_with_data
2024-02-05T16:18:53.465122784Z: [ERROR]      response["model"] = lineJson["model"]
2024-02-05T16:18:53.465126884Z: [ERROR]                          ~~~~~~~~^^^^^^^^^
2024-02-05T16:18:53.465130584Z: [ERROR]  KeyError: 'model'
2024-02-05T16:18:53.465134384Z: [ERROR]  
2024-02-05T16:18:53.465152884Z: [ERROR]  During handling of the above exception, another exception occurred:
2024-02-05T16:18:53.465157184Z: [ERROR]  
2024-02-05T16:18:53.465160484Z: [ERROR]  Traceback (most recent call last):
2024-02-05T16:18:53.465164184Z: [ERROR]    File "/opt/python/3.11.4/lib/python3.11/site-packages/gunicorn/workers/sync.py", line 184, in handle_request
2024-02-05T16:18:53.465167984Z: [ERROR]      for item in respiter:
2024-02-05T16:18:53.465171484Z: [ERROR]    File "/tmp/8dc1e90f6f97d9f/antenv/lib/python3.11/site-packages/werkzeug/wsgi.py", line 256, in __next__
2024-02-05T16:18:53.465175184Z: [ERROR]      return self._next()
2024-02-05T16:18:53.465178684Z: [ERROR]             ^^^^^^^^^^^^
2024-02-05T16:18:53.465182184Z: [ERROR]    File "/tmp/8dc1e90f6f97d9f/antenv/lib/python3.11/site-packages/werkzeug/wrappers/response.py", line 32, in _iter_encoded
2024-02-05T16:18:53.465185984Z: [ERROR]      for item in iterable:
2024-02-05T16:18:53.465189484Z: [ERROR]    File "/tmp/8dc1e90f6f97d9f/app.py", line 425, in stream_with_data
2024-02-05T16:18:53.465193184Z: [ERROR]      yield format_as_ndjson({"error" + str(e)})
2024-02-05T16:18:53.465196884Z: [ERROR]            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2024-02-05T16:18:53.465200384Z: [ERROR]    File "/tmp/8dc1e90f6f97d9f/app.py", line 170, in format_as_ndjson
2024-02-05T16:18:53.465203984Z: [ERROR]      return json.dumps(obj, ensure_ascii=False) + "\n"
2024-02-05T16:18:53.465207684Z: [ERROR]             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2024-02-05T16:18:53.465211184Z: [ERROR]    File "/opt/python/3.11.4/lib/python3.11/json/__init__.py", line 238, in dumps
2024-02-05T16:18:53.465214984Z: [ERROR]      **kw).encode(obj)
2024-02-05T16:18:53.465218384Z: [ERROR]            ^^^^^^^^^^^
2024-02-05T16:18:53.465221884Z: [ERROR]    File "/opt/python/3.11.4/lib/python3.11/json/encoder.py", line 200, in encode
2024-02-05T16:18:53.465225484Z: [ERROR]      chunks = self.iterencode(o, _one_shot=True)
2024-02-05T16:18:53.465229084Z: [ERROR]               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2024-02-05T16:18:53.465232484Z: [ERROR]    File "/opt/python/3.11.4/lib/python3.11/json/encoder.py", line 258, in iterencode
2024-02-05T16:18:53.465236184Z: [ERROR]      return _iterencode(o, 0)
2024-02-05T16:18:53.465239685Z: [ERROR]             ^^^^^^^^^^^^^^^^^
2024-02-05T16:18:53.465243085Z: [ERROR]    File "/opt/python/3.11.4/lib/python3.11/json/encoder.py", line 180, in default
2024-02-05T16:18:53.465246785Z: [ERROR]      raise TypeError(f'Object of type {o.__class__.__name__} '
2024-02-05T16:18:53.465250285Z: [ERROR]  TypeError: Object of type set is not JSON serializable
2024-02-05T16:18:53.496122015Z: [INFO]  fail: Middleware[0]
2024-02-05T16:18:53.496560416Z: [INFO]        Failed to forward request to http://169.254.129.3:8000. Encountered a System.IO.IOException exception after 32272.399ms with message: The response ended prematurely.. Check application logs to verify the application is properly handling HTTP traffic.
2024-02-05T16:18:53.542252109Z: [INFO]  fail: Microsoft.AspNetCore.Server.Kestrel[13]
2024-02-05T16:18:53.542295609Z: [INFO]        Connection id "0HN1554QM4OJH", Request id "0HN1554QM4OJH:00000002": An unhandled exception was thrown by the application.
2024-02-05T16:18:53.545071321Z: [INFO]        System.InvalidOperationException: StatusCode cannot be set because the response has already started.
2024-02-05T16:18:53.545093721Z: [INFO]           at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ThrowResponseAlreadyStartedException(String value)
2024-02-05T16:18:53.545213221Z: [INFO]           at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.Microsoft.AspNetCore.Http.Features.IHttpResponseFeature.set_StatusCode(Int32 value)
2024-02-05T16:18:53.545217821Z: [INFO]           at Microsoft.Azure.AppService.Middleware.Forwarding.RequestForwarder.OnRequest(HttpContext context) in /__w/1/s/src/EasyAuth/Middleware.Forwarding/RequestForwarder.cs:line 90
2024-02-05T16:18:53.545238621Z: [INFO]           at Microsoft.Azure.AppService.Middleware.NetCore.AppServiceMiddleware.InvokeAsync(HttpContext context) in /__w/1/s/src/EasyAuth/Microsoft.Azure.AppService.Middleware.NetCore/AppServiceMiddleware.cs:line 140
2024-02-05T16:18:53.545834924Z: [INFO]           at Microsoft.Azure.AppService.MiddlewareShim.AutoHealing.AutoHealingMiddleware.Invoke(HttpContext context) in /__w/1/s/src/EasyAuth/Middleware.Host/AutoHealing/AutoHealingMiddleware.cs:line 59
2024-02-05T16:18:53.545862024Z: [INFO]           at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)

排查私网环境下应用报错的根本原因，寻求解决方案。

内容的提问来源于stack exchange，提问作者HXK8