[Smartcrawl] I cannot edit main page in dashboard

During the chat we follow those threads to fix the issue on my side
but that does not help.
I contact with host, they enabled "mb_string" and restarted the server, but issue still exist.

I see this in debug.log
PHP Fatal error: Call to undefined function mb_detect_encoding() in /home/++/public_html/wp-content/plugins/wpmu-dev-seo/includes/external/simple_html_dom.php on line 1234