Following error occurs on nginx restart, if the A Record of a Domain (sites-enabled) points to another IP as nginx is running on.
Nginx Host IP: 18.104.22.168
Domain IP (A Record) changed to: 22.214.171.124
nginx configtest (see nginx documentation / full command depends on host os)
Testing nginx configuration: the configuration file /etc/nginx/nginx.conf syntax is
ok[emerg]: bind() to 126.96.36.199:80 failed (99: Cannot assign requested address)
configuration file /etc/nginx/nginx.conf test failed
Remove linked Host Configuration File for related Domain and start nginx as usual.