Nginx actioncable websocket

проверить с помощью curl
 curl -v 'https://dev-ehr.h24.ua/cable' -ps://dev-ehr.h24.ua' -H 'Sec-WebSocket-Key: MIN4DsiwEAutsE11kgG5rg=='  -H 'Upgrade: websocket' -H 'Connection: Upgrade' -H 'Sec-WebSocket-Version: 13'
 
 location /cable {
    proxy_pass http://puma;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $host;
    proxy_set_header X-Forwarded-Proto $scheme; # <- most probably this one is missing
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass_request_headers on; # this is default, but just to be sure

    proxy_buffering off;
    proxy_redirect off;
    break;
  }