Docker compose - (nginx, node.js, react)

Hi, I have some troubles with my application I am using docker-compose and I have 2 backend node.js apps and 1 react fe. Part of docker-compose is nginx. After start everything works fine, but in a while (sometimes hours, sometimes minutes) ngnix starts to return error - “*426 upstream timed out (110: Connection timed out) while reading response header from upstream” The weird part is that on other Droplet everything works fine

upstream fe-wpos {
  server fe-wpos:3000;
}

upstream be-wpos {
  server be-wpos:5000;
}

upstream be-rs-wpos {
  server be-rs-wpos:8081;
}

server {
  listen 80;
  location / {
    proxy_pass http://fe-wpos;
  }
}

server {
  listen 5000;
  location / {
    proxy_pass http://be-wpos;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
  }
}

server {
  listen 8081;
  location / {
    proxy_pass http://be-rs-wpos;
  }
}

I have no idea what is wrong