Fatal error: Uncaught Error: Undefined constant "MB_OVERLOAD_STRING" in /var/www/html/portal_eng/libraries/vendor/joomla/string/src/phputf8/utf8.php:38
Stack trace:
#0 /var/www/html/portal_eng/libraries/vendor/composer/autoload_real.php(66): require()
#1 /var/www/html/portal_eng/libraries/vendor/composer/autoload_real.php(56): composerRequire205c915b9c7d3e718e7c95793ee67ffe()
#2 /var/www/html/portal_eng/libraries/vendor/autoload.php(7): ComposerAutoloaderInit205c915b9c7d3e718e7c95793ee67ffe::getLoader()
#3 /var/www/html/portal_eng/libraries/cms.php(33): require('...')
#4 /var/www/html/portal_eng/includes/framework.php(23): require_once('...')
#5 /var/www/html/portal_eng/index.php(40): require_once('...')
#6 {main}
thrown in /var/www/html/portal_eng/libraries/vendor/joomla/string/src/phputf8/utf8.php on line 38