Call to undefined function Symfony\Polyfill\Intl\Idn\mb_chr()

Fatal error: Uncaught Error: Call to undefined function Symfony\Polyfill\Intl\Idn\mb_chr() in /var/www/html/website.com/wp-content/plugins/cloudflare/vendor/symfony/polyfill-intl-idn/Idn.php:288 Stack trace: #0 /var/www/html/website.com/wp-content/plugins/cloudflare/vendor/symfony/polyfill-intl-idn/Idn.php(333): Symfony\Polyfill\Intl\Idn\Idn::mapCodePoints() #1 /var/www/html/website.com/wp-content/plugins/cloudflare/vendor/symfony/polyfill-intl-idn/Idn.php(161): Symfony\Polyfill\Intl\Idn\Idn::process() #2 /var/www/html/website.com/wp-content/plugins/cloudflare/vendor/symfony/polyfill-intl-idn/bootstrap.php(140): Symfony\Polyfill\Intl\Idn\Idn::idn_to_ascii() #3 /var/www/html/website.com/wp-content/plugins/cloudflare/src/WordPress/WordPressClientAPI.php(18): idn_to_ascii() #4 /var/www/html/website.com/wp-content/plugins/cloudflare/src/WordPress/Hooks.php(148): CF\WordPress\WordPressClientAPI->getZoneTag() #5 /var/www/html/website.com/wp-content/plugins/cloudflare/src/W in /var/www/html/website.com/wp-content/plugins/cloudflare/vendor/symfony/polyfill-intl-idn/Idn.php on line 288

Hi Guys Facing this issue I have recently migrated my website from one shared hosting to a dedicated one when I Click on save button on my contact form 7 form this issue arises I don’t the main cause of this issue can it might be due to the php version 7.4 currently using and on my shared hosting they were using 8.1.

and yes I am using cloudflare plugin also same version on both end.