Connection with UiServer Websocket was lost. Reconnecting...

I'm running a proxy server and when I try to connect to my server through domain this error is out

nginx conf (part of)

map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}

upstream zeronet_backend {
server (my ip, not localhost):43110;
}

server {
listen 80;
listen [::]:80;
server_name (my domain);
return 301 https://$host$request_uri;
}

server {
listen 443;
listen [::]:443;
server_name (my domain);
#SSL
ssl_certificate /etc/nginx/ssl/server.crt;
ssl_certificate_key /etc/nginx/ssl/server.key;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;
ssl_ecdh_curve secp384r1;
ssl_ciphers ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!3DES:!MD5:!PSK:!RC4; # no RC4 and known insecure cipher

#LOG
access_log /var/log/nginx/zeronet/default.log;
error_log /var/log/nginx/zeronet/error.log;

#LOCATION

location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header User-Agent $http_user_agent;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_pass http://zeronet_backend;
proxy_http_version 1.1;
}
location /Websocket {
proxy_pass http://zeronet_backend;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
}
#LOCATION END

}

zeronet conf

[global]
ui_ip = 0.0.0.0
ui_port = 43110
ui_host = (my domain)

What's the problem?