Chat, socket often disconnecting

[Maciej Bąk 0]

2020/04/24 10:42:11 [error] 17609#17609: *3657877 connect() failed (111: Connection refused) while connecting to upstream, client: 37.47.200.53, server: ziomalum.pl, request: "GET /socket.io/?EIO=3&transport=polling&t=N6hMVu_ HTTP/2.0", upstream: "http://127.0.0.1:4567/socket.io/?EIO=3&transport=polling&t=N6hMVu_", host: "ziomalum.pl", referrer: "https://ziomalum.pl/recent"

also in browser I see:

VM113:1 GET https://ziomalum.pl/socket.io/?EIO=3&transport=polling&t=N6hMUWl 502

my config.json:

cat config.json 
{
    "url": "https://ziomalum.pl",
    "secret": "...",
    "database": "mongo",
    "bindaddress": "localhost",
    "mongo": {
        "host": "127.0.0.1",
        "port": "27017",
        ...
    },
    "series": true,
    "socket.io": {
	"origins": "https://ziomalum.pl:* https://forum.ziomalum.pl:*"
   }
}

can someone help me what is causing this issue ?
thanks!

[Maciej Bąk 0]

ok problem was because of global chat plugin