I got the same PHP fatal error as this post, which I believe resulted in a 502 error on my site. I’ve since updated the theme from 4.3.1 to 4.3.3, so I don’t know if that resolved anything, but wanted to see if there was a resolution to the last posting?
Currently running WP 5.7.1 / PHP 7.3.28.
PHP Fatal error: Uncaught Error: Call to undefined function x_get_view() in /var/www/vhosts/____________.com/httpdocs/wp-content/themes/pro/index.php:16/nStack trace:\n#0 {main}/nthrown in /var/www/vhosts/____________.com/httpdocs/wp-content/themes/pro/index.php on line 16'