It is not always convenient for mail to be located at /webmail. But this configuration is in Vesta CP by default. While the developers of the panel have not done the same thing that we are going to do, this will have to be repeated with each new server installation.

So, let’s start:

1. Create a web domain in Vesta CP: mail.your-domain.com (it can be immediately configured on https using the new, built-in ability to generate ssl certificates – letsencrypt).

2. Delete the links to the roundcube and / or roundcube.inc in /etc/apache2 (in the sub-folders conf.d, sites-available, sites-enabled) and /etc/nginx (in the subfolder conf.d).

3. Edit Nginx configuration file (for simplicity, we use /home/admin – the standard user folder in vesta):

/home/admin/conf/web/nginx.conf
/home/admin/conf/web/snginx.conf

replace
root /home/admin/web/your-domain/public_html;
to
root /var/lib/roundcube;

4. Edit Apache configuration file:

/home/admin/conf/web/apache.conf
/home/admin/conf/web/sapache.conf

replace
DocumentRoot /home/admin/web/mail.nebulonis.com/public_html
to
DocumentRoot /var/lib/roundcube/

and add:

# Access to tinymce files
<Directory "/usr/share/tinymce/www/">
    Options Indexes MultiViews FollowSymLinks
    AllowOverride None
    Order allow,deny
    allow from all
</Directory>

<Directory /var/lib/roundcube/>
    Options +FollowSymLinks
    # This is needed to parse /var/lib/roundcube/.htaccess. See its
    # content before setting AllowOverride to None.
    AllowOverride All
    order allow,deny
    allow from all
</Directory>

# Protecting basic directories:
<Directory /var/lib/roundcube/config>
    Options -FollowSymLinks
    AllowOverride None
</Directory>

<Directory /var/lib/roundcube/temp>
    Options -FollowSymLinks
    AllowOverride None
    Order allow,deny
    Deny from all
</Directory>

<Directory /var/lib/roundcube/logs>
    Options -FollowSymLinks
    AllowOverride None
    Order allow,deny
    Deny from all
</Directory>

5. Let’s check the syntax:
apachectl configtest
nginx -t

6. Restart:
apachectl graceful
service nginx restart

7. And, finally, in the panel settings (https://your-ip-or-address:8083/edit/server/) SERVER -> CONFIGURE In the tab MAIL -> Webmail URL change to new (https://mail.your-domain.com)