Reason: This module is not available for PHP 7.2 yet, you need to install the 7.1 version and link it to 7.2
php7.2 will solve the issue here. Below are the steps to configure 7.1 version mcrypt with
sudo apt install php7.1-mcrypt
Create symbolic link to
sudo ln -s /etc/php/7.1/mods-available/mcrypt.ini /etc/php/7.2/mods-available/
sudo phpenmod mcrypt Thanks StackOverflow!