If your cPanel PHP was updated recently then you will see this error on the website.
You will have to update the composer packages. Go the the laravel main directory and run below command
/opt/cpanel/ea-php73/root/usr/bin/php /opt/cpanel/composer/bin/composer update
Above is for site you using php 7.3. If you are using other php version then use the correct php path to that version.