Fatal error: Uncaught Error: Call to undefined function Bitrix\Main\IO\mb_substr() in /mnt/disk2/www/isg/bitrix/modules/main/lib/io/path.php:77
Stack trace:
#0 /mnt/disk2/www/isg/bitrix/modules/main/lib/localization/loc.php(70): Bitrix\Main\IO\Path::normalize()
#1 /mnt/disk2/www/isg/bitrix/modules/main/lib/orm/fields/validators/validator.php(15): Bitrix\Main\Localization\Loc::loadMessages()
#2 /mnt/disk2/www/isg/bitrix/modules/main/lib/loader.php(436): require_once('...')
#3 [internal function]: Bitrix\Main\Loader::autoLoad()
#4 /mnt/disk2/www/isg/bitrix/modules/main/include/compatibility.php(28): class_alias()
#5 /mnt/disk2/www/isg/bitrix/modules/main/include/autoload.php(203): require_once('...')
#6 /mnt/disk2/www/isg/bitrix/modules/main/start.php(21): require_once('...')
#7 /mnt/disk2/www/isg/bitrix/modules/main/include.php(13): require_once('...')
#8 /mnt/disk2/www/isg/bitrix/modules/main/include/prolog_before.php(19): require_once('...')
#9 /mnt/disk2/www/isg/bitrix/modules/main/include/prolog.php(10): require_once('...')
#10 /mnt/disk2/www/isg/bitrix/header.php(1): require_once('...')
#11 /mnt/disk2/www/isg/news/index.php(2): require('...')
#12 {main}
thrown in /mnt/disk2/www/isg/bitrix/modules/main/lib/io/path.php on line 77