Fatal error: Class “DOMDocument” not found

I am hoping someone can assist a novice, please.

I suddenly am no longer able to print the invoices nor packing lists in PDF and the auto emails are also being sent as plain text (no pdfs attached). My wordpress and all plugins are all up to date. I have removed the plugin and reinstalled and i have also tried using another plugin (which also gave an error).

Here is the error message when i try and print the pdf invoice or packing slip:

Fatal error: Class “DOMDocument” not found/chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/wcpdf-functions.php (578)#0 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document-methods.php(210): wpo_wcpdf_sanitize_html_content() #1 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document-methods.php(222): WPO\WC\PDF_Invoices\Documents\Order_Document_Methods->get_shipping_address() #2 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/templates/Simple/packing-slip.php(42): WPO\WC\PDF_Invoices\Documents\Order_Document_Methods->shipping_address() #3 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document.php(1213): include(‘/chroot/home/fe…’) #4 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document.php(1071): WPO\WC\PDF_Invoices\Documents\Order_Document->render_template() #5 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document.php(1026): WPO\WC\PDF_Invoices\Documents\Order_Document->get_html() #6 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/documents/abstract-wcpdf-order-document.php(1093): WPO\WC\PDF_Invoices\Documents\Order_Document->get_pdf() #7 /chroot/home/fendeck/fendeck.co.za/html/online/wp-content/plugins/woocommerce-pdf-invoices-packing-slips/includes/class-wcpdf-main.php(568): WPO\WC\PDF_Invoices\Documents\Order_Document->output_pdf() #8 /chroot/home/fendeck/fendeck.co.za/html/online/wp-includes/class-wp-hook.php(324): WPO\WC\PDF_Invoices\Main->generate_document_ajax() #9 /chroot/home/fendeck/fendeck.co.za/html/online/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters() #10 /chroot/home/fendeck/fendeck.co.za/html/online/wp-includes/plugin.php(517): WP_Hook->do_action() #11 /chroot/home/fendeck/fendeck.co.za/html/online/wp-admin/admin-ajax.php(192): do_action() #12 {main}