google-app-engine - GCP Cloud http负载均衡器上的websocket_handshake_failed，响应为403

Question

websocket_handshake_failed我们在 GCP 负载均衡器上获得了数千个。我们的环境是：具有自动缩放功能的 App Engine Flex 环境 + Postgress 云 SQL 我们有一个聊天 SaaS 应用程序，因此我们使用套接字。在日志记录中，我看到websocket_handshake_failed每小时 +1000，

以下是单个错误的日志示例：

    {
insertId: "1yr7yf8g129xnqm"
jsonPayload: {2}
httpRequest: {
requestMethod: "GET"
requestUrl: "https://platform.businesschat.io/socket/websocket?auth_token=SFMyNTY.g2gDdAAAAAFkAAd1c2VyX2lkYR5uBgBpppTkeAFiAAFRgA.KRJF8oZWOOtsOS0aqNUzf8OJgip-znonz31WSPGwUlQ&vsn=2.0.0"
requestSize: "2382"
status: 403
responseSize: "231"
userAgent: "Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.114 Safari/537.36"
remoteIp: "188.54.82.167"
serverIp: "10.156.0.30"
}
resource: {
type: "http_load_balancer"
labels: {
target_proxy_name: ""
url_map_name: ""
project_id: "businesschat-platform"
forwarding_rule_name: ""
backend_service_name: "aef-default-20210418t185059-bs"
zone: "global"
}
}
timestamp: "2021-04-19T10:05:16.050343Z"
severity: "WARNING"
logName: "projects/businesschat-platform/logs/requests"
trace: "projects/businesschat-platform/traces/2205a954ba0c5d518574a6b00316fa92"
receiveTimestamp: "2021-04-19T10:05:17.924136122Z"
spanId: "692567857ac6b22b"
}

在前端，我得到一个样本connection: close error，不确定是否相关：