Critical Error

I am having php 7.4 and it gives me critical error when I click on download pdf button.

However the plugin works on test site with the same php and wordpress version.

Fatal error: Uncaught Mpdf\MpdfException: Invalid size representation “calc(100% – ( 0 * 30px ) )” in dk-pdf/vendor/mpdf/mpdf/src/SizeConverter.php:35 Stack trace: #0 dk-pdf/vendor/mpdf/mpdf/src/Mpdf.php(19781): Mpdf\SizeConverter->convert(‘calc(100% – ( 0…’, 180.00155555556, 3.8805555555556, false) #1 /dk-pdf/vendor/mpdf/mpdf/src/Tag/BlockTag.php(385): Mpdf\Mpdf->setCSS(Array, ‘BLOCK’, ‘DIV’) #2 dk-pdf/vendor/mpdf/mpdf/src/Tag.php(239): Mpdf\Tag\BlockTag->open(Array, Array, 7) #3 dk-pdf/vendor/mpdf/mpdf/src/Mpdf.php(15310): Mpdf\Tag->OpenTag(‘DIV’, Array, Array, 7) #4dk-pdf/includes/dkpdf-functions.php(198): Mpdf\Mpdf->WriteHTML(‘ <div class=”dk…’) #5?/wp-includes/class-wp-hook.php(310): dkpdf_output_pdf(Object(WP)) #6dk-pdf/vendor/mpdf/mpdf/src/SizeConverter.php?on line?35

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