502 error on django application after server reboot

this is my gunicorn.service file.

[Unit]
Description=gunicorn daemon
Requires=gunicorn.socket
After=network.target

[Service]
User=sammy
Group=www-data
WorkingDirectory=/home/sammy/myprojectdir
ExecStart=/var/www/html/new_remove_bg/newvenv/bin/gunicorn \
          --access-logfile - \
          --workers 3 \
          --bind unix:/run/gunicorn.sock \
          /var/www/html/new_remove_bg/mysite/mysite.wsgi:application

[Install]
WantedBy=multi-user.target




ExecStart=/var/www/html/new_remove_bg/newvenv/bin/gunicorn --access-logfile - --workers 3 --bind unix:/var/www/html/new_remove_bg/mysite/mysite.sock myproject.wsgi:application

this is my new_remove_bg file

server {
    listen 80;
    server_name slicebg.com;

    location = /favicon.ico { access_log off; log_not_found off; }
    location /static/ {
        root /var/www/html/new_remove_bg/mysite;
    }

    location / {
        include proxy_params;
        proxy_pass http://unix:/var/www/html/new_remove_bg/mysite/mysite.sock;
    }
}

Please guide me how to overcome this issue and i am trying to deploy django application.