how to fix 502 nginx?

I have plastic scm on my localhost and nginx with my.domain.com. I want my.domain.com link to open plastic on port 80(forward proxy). I made a config in sites-available but get 502 bad gateway. Please look through and help. Sorry for my english.

server {
listen 80;
root /var/www/my.domaim.com;
server_tokens off;
server_name my.domaim.com;
location / {
    proxy_pass http://127.0.0.1:7178;
}
location /.well-known/acme-challenge/ {
    alias /var/lib/dehydrated/;
}
}  

server {
listen 443 ssl;
server_name my.domaim.com;
ssl_certificate /etc/dehydrated/certs/my.domaim.com/fullchain.pem;
ssl_certificate_key /etc/dehydrated/certs/my.domaim.com/privkey.pem;
}