Fatal error: Uncaught Error: Call to undefined function Dompdf\mb_internal_encoding() in /var/www/public_html/plugins/pdfcreater/vendor/dompdf/dompdf/src/Dompdf.php:295

Check if mbstring is installed
Run in terminal:

• If nothing shows, it’s not installed.

Install mbstring
Depending on your OS:

• Ubuntu/Debian

  sudo apt-get update
sudo apt-get install php-mbstring
sudo systemctl restart apache2


• CentOS/RHEL

  sudo yum install php-mbstring
sudo systemctl restart httpd


• If using PHP-FPM

  sudo systemctl restart php*-fpm


Enable extension in php.ini
Open your php.ini and make sure:

Then restart Apache/Nginx/PHP-FPM.

Verify again

You should see mbstring.

Check in phpinfo()
Create a file info.php in your web root:

Open it in browser and check that mbstring support = enabled.