have created the following simple conf ..

#user nobody;
worker_processes 1;

#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
pid logs/nginx.pid;
events {
worker_connections 1024;
}

http {
include mime.types;
default_type application/octet-stream;
limit_conn_zone $remote_user zone=peruser:10m;


log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;

sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;


server {
listen 9901;
server_name 5.152.204.130;

location = / {
auth_basic "Restricted";
auth_basic_user_file /usr/local/nginx/users/user;
limit_conn peruser 1;
proxy_pass http://192.168.1.200:44444;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_redirect off;
proxy_buffering off;
proxy_ignore_client_abort off;
proxy_connect_timeout 180;
proxy_send_timeout 21600;
proxy_read_timeout 21600;
proxy_max_temp_file_size 0;


}

#if ($http_user_agent ~* "vlc" ) {return 403; }
error_page 403 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/local/nginx/html;
}

}

}



Connected to this conf after 50 people are starting to freeze.
( I saw the other stream in the port flowed smoothly but freezes when I connect nginx port. )

I wonder where did I go wrong?
thank you in advance ....