Also when install the trial of power plesk (the movil app of plesk) this error occurs. I hope someone look at this issue. Thank you MladenM for the solution.
Cheers.
1.- Is with Nginx but thanks, is the right clue what I needed.
2.- That will be global, I need only 1 domain, it will be nice if I could modify just 1 domain and the changes will keep
Index - System Overview -> Add or Remove Components -> Plesk webmails support. If there's no one check, check one or both. From here you're alone, I'm not using it. If there is anything check, you have to view the configurations.
How can I customize/add a configuration for a vhost in nginx. I want to put proxy_pass for Node.js into a subdomain of a vhost. All files I look it says: DO NOT MODIFY THIS FILE BECAUSE IT WAS GENERATED AUTOMATICALLY