Fatal error: Uncaught TypeError: DOMNode::replaceChild(): Argument #1 ($node) must be of type DOMNode, null given in /var/www/html/wp-content/plugins/markup-markdown/MarkupMarkdown/Parsedown/Extra.php:501 Stack trace: #0 /var/www/html/wp-content/plugins/markup-markdown/MarkupMarkdown/Parsedown/Extra.php(501): DOMNode->replaceChild(NULL, Object(DOMElement)) #1 /var/www/html/wp-content/plugins/markup-markdown/MarkupMarkdown/Parsedown/Extra.php(236): MarkupMarkdown\Parsedown\Extra->processTag('blockMarkupComplete(Array) #3 /var/www/html/wp-content/plugins/markup-markdown/MarkupMarkdown/Parsedown/Parsedown.php(43): MarkupMarkdown\Parsedown\Parsedown->lines(Array) #4 /var/www/html/wp-content/plugins/markup-markdown/MarkupMarkdown/Parsedown/Extra.php(50): MarkupMarkdown\Parsedown\Parsedown->text('...') #5 /var/www/html/wp-content/plugins/markup-markdown/MarkupMarkdown/Core/Parser.php(184): MarkupMarkdown\Parsedown\Extra->text('\nmarkdown2html('\nfinal_html('\nlive_html('\nformat_mmd2html('\napply_filters('\ncontent_data('\npost_content_mmd2html('\napply_filters('\n