Please Edit Postfix Guides Email with Postfix, Dovecot and MariaDB on CentOS 7
Skip .......... $virtual_mailbox_limit_maps
postconf -e 'virtual_create_maildirsize = yes'
postconf -e 'virtual_maildir_extended = yes'
The following BOLD Code add to postfix main,cf will show Error
postfix: /usr/sbin/postconf: warning: /etc/postfix/main.cf: undefined parameter: virtual_mailbox_limit_maps
postfix: /usr/sbin/postconf: warning: /etc/postfix/main.cf: unused parameter: virtual_create_maildirsize=yes
postfix: /usr/sbin/postconf: warning: /etc/postfix/main.cf: unused parameter: virtual_maildir_extended=yes