My client send a request with size >8KB to my Nginx reverse proxy server. There is an upstream gRPC server behind Nginx.

When I check the error code, it is rpc error: code = Unavailable desc = closing transport due to: connection error: desc = "error reading from server: EOF", received prior goaway: code: ENHANCE_YOUR_CALM

I am so confused with why did I receive such error code?

I know that the limitation of the size of header is specified in my nginx rule. By default, it is

large_client_header_buffers 4 8k;

Does the gRPC client interpret the response from Nginx wrongly?

After I increase the limitation, the error code does not show up again.

According to the description of Nginx document,

A request line cannot exceed the size of one buffer, or the 414 (Request-URI Too Large) error is returned to the client. A request header field cannot exceed the size of one buffer as well, or the 400 (Bad Request) error is returned to the client.