After racking my brains over and over, I solved it like this. underscores_in_headers on; location / { grpc_read_timeout 300s; grpc_send_timeout 300s; grpc_socket_keepalive on; if ($http_content_type = "application/grpc") { grpc_pass grpc://collector.teste.com.br:4317; } proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $http_connection; proxy_http_version 1.1; } I added this configuration to the advanced nginx proxy manager for the domain I created, pointing to 4317.