1. Check whether you have mcrypt module or not

   php -m | grep mcrypt

2. If not present, install it

   sudo apt-get install php7.0-mcrypt

3. Enable the module

   sudo phpenmod mcrypt

4. Restart Apache and php-fpm

   sudo service apache2 restart

   sudo service php-fpm restart

There are chances that it may not work if you have two php installed in the system. One with Apace/php-fpm and one through CLI. In order to be sure that mcrypt is enabled. Creat a file testmcrypt.php in your root and with below code.

<?php
phpinfo();

Run the file your browser and check if you can see the mcrypt module in the page.

1. Check whether you have mcrypt module or not

php -m | grep mcrypt

2. If not present, install it

sudo apt-get install php7.0-mcrypt

3. Enable the module

sudo phpenmod mcrypt

4. Restart Apache and php-fpm

sudo service apache2 restart

sudo service php-fpm restart

There are chances that it may not work if you have two php installed in the system. One with Apace/php-fpm and one through CLI. In order to be sure that mcrypt is enabled. Creat a file testmcrypt.php in your root and with below code.

<?php
phpinfo();

Run the file your browser and check if you can see the mcrypt module in the page.