NGINX and SSL issue

I need to switch to "apache only" after I installed an autoSSL certificate on one of my domains.

If I try to switch again to "Apache + nginx" I got this error:

Nginx ERROR Detected ! nginx: [emerg] host not found in "null:443" of the "listen" directive in /etc/nginx/conf.d/guidadelgusto.com_ssl.conf:4 nginx: configuration file /etc/nginx/nginx.conf test failed

If I delete the new certificate I can switch to "apache + nginx" without problem.

looks like IP address is missing for your account/domain as you get "null:443" try to check if ip is correctly set for that account.
If you still face the issue the best would be to contact cwp support team to check it
http://centos-webpanel.com/contact

Go to » https://YOURSERVERIP:2031/admin/index.php?module=list_domains
and delete the domain "guidadelgusto.com"
This will also delete the SSL certificate and your problem .conf file.
Check it, if it is still there delete "/etc/nginx/conf.d/guidadelgusto.com_ssl.conf" manually over SSH or FTP!

Then go to https://YOURSERVERIP:2031/admin/index.php?module=add_domain 
and add the domain again.
Now you should be fine with SSL and with "Apache + nginx".