nginx 转发 gprc 请求， UNAVAILABLE: HTTP status code 502

client 报错：
UNAVAILABLE: HTTP status code 502

nginx 日志：
upstream sent too large http2 frame: 1377025 while reading response header from upstream, client: 127.0.0.1, server: hsltest.org1.peer0, request: "POST /protos.Events/Chat HTTP/2.0"

nginx 需要配置那些信息啊

nginx 配置如下

http { include mime.types; default_type application/octet-stream; log_format main '$remote_addr - $upstream_addr - [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" "-" "$host"'; access_log logs/http.access.log; sendfile on; tcp_nopush on; tcp_nodelay on; keepalive_timeout 240; grpc_buffer_size 8m; http2_max_field_size 2m; http2_max_header_size 2m; proxy_buffer_size 2m; proxy_buffers 4 2m; proxy_busy_buffers_size 2m; http2_recv_buffer_size 2m; http2_chunk_size 2m; server_names_hash_bucket_size 128; ssl on; ssl_certificate ssh/org1.peer0.tls.cer; ssl_certificate_key ssh/org1.peer0.tls.key; ssl_client_certificate ssh/org1.tlsca.cer; ssl_verify_client on; server { listen 1051 ssl http2; server_name hsltest.org1.peer0; location / { grpc_pass grpc://192.168.235.128:1051; } } }