Zend certified PHP/Magento developer

Connect domain name with Linux VPS server ip using nginx

I have a VPS Linux (Ubuntu) server and I would like to connect a domain name with my server IP through nginx. I have checked the following:

$ sudo systemctl reload nginx

nginx.service is not active, cannot reload

$ sudo service nginx start
Job for nginx.service failed because the control process exited with error code.
See "systemctl status nginx.service" and "journalctl -xe" for details.

$ systemctl status nginx.service
● nginx.service - A high performance web server and a reverse proxy server
     Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Sun 2022-05-15 18:53:40 CEST; 11s ago

$ sudo nginx -t
nginx: [emerg] unknown "connection_upgrade" variable
nginx: configuration file /etc/nginx/nginx.conf test failed


I would appreciate if someone could help me with this issue.