==== Required information ====
-iRedMail =  0.9.8 MYSQL edition.
web server = nginx
NAME="Ubuntu"
VERSION="18.04 LTS (Bionic Beaver)"
====

webmail shows 404 not found
nginx: will not start with the following line enabled in /etc/nginx/templates/fastcgi-php.tmpl

# Handle PHP files with upstream handler
#fastcgi_pass php_workers;

It looks like the other admin may have updated php from 7.1 to 7.2

I have moved /etc/php/7.2 to /etc/php/7.2.old and copied /etc/php/7.1 to /etc/php7.2
Updated /etc/php/7.2/fpm/pool.d:

;listen = /run/php/php7.1-fpm.sock
listen = /var/run/php-fpm.socket

everything is working but webmail,