Thanks for the email.
Do you know what version of PHP you are using? I suspect that perhaps the PHP version is fairly old. You can find this information in cPanel or your hosting provider would know it. Or you can also install the “Display PHP Version” plugin and it will show your version in your WordPress dashboard in the “At a Glance” section. Then just delete the plugin once you know your version.
WordPress recommends a PHP version of 5.6 or greater. The fastest solution may be to upgrade PHP if you’re on an older version.