A common not found during trial run of some software 🙂

Fatal error: Call to undefined function mb_strlen() in file.php on line 123

Missing dependency :

on Debian, Ubuntu and other friends :

apt-get install php7.0-mbstring

on Centos, RHEL and other friends :

yum install php-mbstring

Or in my case PHP 7 using the webtatic.com repo

yum install php70w-mbstring