Description

hello:
we have two apisix env(such as A and B), when we use apisix to proxy grpc service, A always OK, but in B, when you first time send a request. It returns 502, but the following request all returns 200. and I also found that when we send a request in B, after a while，send request again, then the first request always return 502, the following return 200. I am confused of such thing. because A and B env apisix version and depends are same.

when 502 occurs. the following error occurs:
`

[error] 20620#20620: *327238 no connection data found for keepalive http2 connection while sending request to upstream

`

I want to get some idea from you. what causes it and how to solve it.
hope yours. thanks.

Environment

• APISIX version (run apisix version): v2.12.0
• Operating system (run uname -a): the problem env is :Linux 3.10.0-1160.36.2.el7.x86_64. the good env is: Linux 3.10.0-957.21.3.el7.x86_64
• OpenResty / Nginx version (run openresty -V or nginx -V): nginx version: openresty/1.21.4.1
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info): 3.5.0
• APISIX Dashboard version, if relevant:
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):