If you use Yoast for WP and press button 'Remove Yoast SEO Comments' - you can show this errors:

Fatal error: Uncaught Error: Call to undefined method RYSC::head_product_name() 
in /home/youraccount/sitename.com/www/wp-content/plugins/remove-yoast-seo-comments/remove-yoast-seo-comments.php(110) : eval()'d code:17 
Stack trace: #0 /home/youraccount/sitename.com/www/wp-content/plugins/remove-yoast-seo-comments/remove-yoast-seo-comments.php(110): eval() 
#1 /home/youraccount/sitename.com/www/wp-includes/class-wp-hook.php(286): RYSC->rewrite('') 
#2 /home/youraccount/sitename.com/www/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) 
#3 /home/youraccount/sitename.com/www/wp-includes/plugin.php(453): WP_Hook->do_action(Array) 
#4 /home/youraccount/sitename.com/www/wp-includes/general-template.php(2614): do_action('wp_head') 
#5 /home/youraccount/sitename.com/www/wp-content/themes/Newspaper/header.php(11): wp_head() 
#6 /home/youraccount/sitename.com/www/wp-includes/template.php(688): require_once('/home/youraccount/...') 
#7 /home/youraccount/sitename.com/www/wp-includes/template.php(647): load_template in /home/youraccount/sitename.com/www/wp-content/plugins/remove-yoast-seo-comments/remove-yoast-seo-comments.php(110) : eval()'d code on line 17

To fix it - Go to FTP -> open www/wp-content/plugins/ -> find folder remove-yoast-seo-comments and remove it or delete or rename (-remove-yoast-seo-comments)

Work done!

If you update your hosting to v7.1 & more - you can look same notification 'Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; plgContentJw_sigpro has a deprecated constructor in .../www/plugins/content/jw_sigpro/jw_sigpro.php on line 19'

This code fix this problem you need Open plugins/content/jw_sigpro/jw_sigpro.php find this code in line 28:

function plgContentJw_sigpro(&$subject, $params)
	{
		parent::__construct($subject, $params);

		// Define the DS constant under Joomla! 3.0
		if (!defined('DS'))
		{
			define('DS', DIRECTORY_SEPARATOR);
		}
	}

 And replase it to this code:

public function __construct(&$subject, $params) {
	parent::__construct($subject, $params);

	// Define the DS constant under Joomla! 3.8.2+
	if (!defined('DS')){
		define('DS', DIRECTORY_SEPARATOR);
	}
}

Awesome - it work done! :-)

If you see same problem with jw_sig.php  - just download free new plugin from GitHub and install it: https://github.com/joomlaworks/simple-image-gallery