Call to undefined function Symfony\Polyfill\Mbstring\iconv_strpos() error laravel 5.4

I am uploading a laravel 5.4 project to cpanel server. And i am serve with

PHP Fatal error:  Call to undefined function Symfony\Polyfill\Mbstring\iconv_strpos()

on server.

I have done

composer require symfony/polyfill-iconv

However, it does not change the error message. What thing i might miss out?

via Brian Ruchiadi