nginx + ocelot+.net core signalr 关于websocket无法正常握手的问题

在发送post请求到 negotiate时，ocelot里提示
requestId: 0HM4FAJCPR76R:00000001, previousRequestId: no previous request id, message: Error Code: UnableToCompleteRequestError Message: Error making http request, exception: System.Net.Http.HttpRequestException: Resource temporarily unavailable ---> System.Net.Sockets.SocketException: Resource temporarily unavailable
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
at System.Threading.Tasks.ValueTask1.get_Result() at System.Net.Http.HttpConnectionPool.CreateConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken) at System.Threading.Tasks.ValueTask1.get_Result()
at System.Net.Http.HttpConnectionPool.WaitForCreatedConnectionAsync(ValueTask1 creationTask) at System.Threading.Tasks.ValueTask1.get_Result()
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
at Ocelot.Requester.HttpClientHttpRequester.GetResponse(DownstreamContext context) errors found in ResponderMiddleware. Setting error response for request path:/kf/negotiate, request method: POST

整个项目的流程是这样的：
请求->nginx->ocelot->api+signalr
网上g了，stackoverflow也翻了，各种试了，看看有没有大神遇到过同样的问题

回答

先直接connect到api, 在测试ocelot+api, 在测试nginx+ocelot+api, 总归是某个地方的设置有问题.