ral.attachment_redirect_default' );

		/**
		 * Redirect atachment to its parent post.
		 *
		 * @param string  $redirect URL as calculated for redirection.
		 * @param WP_Post $post     Current post instance.
		 */
		Helper::redirect( $this->do_filter( 'frontend/attachment/redirect_url', $redirect, $post ), 301 );
		exit;
	}

	/**
	 * Redirect date & author archives if the setting is enabled.
	 */
	public function archive_redirect() {
		global $wp_query;

		if (
			( Helper::get_settings( 'titles.disable_date_archives' ) && $wp_query->is_date ) ||
			( true === Helper::get_settings( 'titles.disable_author_archives' ) && $wp_query->is_author )
		) {
			Helper::redirect( get_bloginfo( 'url' ), 301 );
			exit;
		}
	}

	/**
	 * Adds the RSS header and footer messages to the RSS feed item content.
	 *
	 * @param string $content Feed item content.
	 *
	 * @return string
	 */
	public function embed_rssfooter( $content ) {
		return $this->embed_rss( $content, 'full' );
	}

	/**
	 * Adds the RSS header and footer messages to the RSS feed item excerpt.
	 *
	 * @param string $content Feed item excerpt.
	 *
	 * @return string
	 */
	public function embed_rssfooter_excerpt( $content ) {
		return $this->embed_rss( $content, 'excerpt' );
	}

	/**
	 * Add data-ampdevmode attribute to enqueued scripts.
	 *
	 * @since 1.0.45
	 *
	 * @param string $tag    The script tag.
	 * @param string $handle The script handle.
	 *
	 * @return string Modified script tag.
	 */
	public function add_amp_dev_mode_attributes( $tag, $handle ) {
		if ( ! in_array( $handle, [ 'rank-math', 'jquery-core', 'jquery-migrate' ], true ) ) {
			return $tag;
		}

		return preg_replace( '/(?<=<script)(?=\s|>)/i', ' data-ampdevmode', $tag );
	}

	/**
	 * Add data-ampdevmode attributes to the elements that need it.
	 *
	 * @since 1.0.45
	 *
	 * @param string[] $xpaths XPath queries for elements that should get the data-ampdevmode attribute.
	 *
	 * @return string[] XPath queries.
	 */
	public function add_amp_dev_mode_xpaths( $xpaths ) {
		$xpaths[] = '//script[ contains( text(), "var rankMath" ) ]';
		$xpaths[] = '//*[ @id = "rank-math-css" ]';
		$xpaths[] = '//a[starts-with(@href, "tel://")]';
		return $xpaths;
	}

	/**
	 * Inserts the RSS header and footer messages in the RSS feed item.
	 *
	 * @param string $content Feed item content.
	 * @param string $context Feed item context, 'excerpt' or 'full'.
	 *
	 * @return string
	 */
	private function embed_rss( $content, $context = 'full' ) {
		if ( false === $this->can_embed_footer( $content, $context ) ) {
			return $content;
		}

		$before = $this->get_rss_content( 'before' );
		$after  = $this->get_rss_content( 'after' );

		if ( '' === $before && '' === $after ) {
			return $content;
		}

		if ( 'excerpt' === $context && '' !== trim( $content ) ) {
			$content = wpautop( $content );
		}

		return $before . $content . $after;
	}

	/**
	 * Check if we can add the RSS footer and/or header to the RSS feed item.
	 *
	 * @copyright Copyright (C) 2008-2019, Yoast BV
	 * The following code is a derivative work of the code from the Yoast(https://github.com/Yoast/wordpress-seo/), which is licensed under GPL v3.
	 *
	 * @param string $content Feed item content.
	 * @param string $context Feed item context, either 'excerpt' or 'full'.
	 *
	 * @return bool
	 */
	private function can_embed_footer( $content, $context ) {
		/**
		 * Allow the RSS footer to be dynamically shown/hidden.
		 *
		 * @param bool   $show_embed Indicates if the RSS footer should be shown or not.
		 * @param string $context    The context of the RSS content - 'full' or 'excerpt'.
		 */
		if ( false === $this->do_filter( 'frontend/rss/include_footer', true, $context ) ) {
			return false;
		}

		return is_feed();
	}

	/**
	 * Get RSS content for specified location.
	 *
	 * @param string $which Location ID.
	 *
	 * @return string
	 */
	private function get_rss_content( $which ) {
		$content = $this->do_filter( 'frontend/rss/' . $which . '_content', Helper::get_settings( 'general.rss_' . $which . '_content' ) );

		return '' !== $content ? wpautop( $this->rss_replace_vars( $content ) ) : $content;
	}

	/**
	 * Replace variables with the actual values in RSS header and footer messages.
	 *
	 * @param string $content The RSS content.
	 *
	 * @return string
	 */
	private function rss_replace_vars( $content ) {
		global $post;

		/**
		 * Add nofollow for the links in the RSS header and footer messages. Default: true.
		 *
		 * @param bool $unsigned Whether or not to follow the links in RSS feed, defaults to true.
		 */
		$no_follow = $this->do_filter( 'frontend/rss/nofollow_links', true );
		$no_follow = true === $no_follow ? 'rel="nofollow" ' : '';

		$author_link = '';
		if ( is_object( $post ) ) {
			$author_link = '<a ' . $no_follow . 'href="' . esc_url( get_author_posts_url( $post->post_author ) ) . '">' . esc_html( get_the_author() ) . '</a>';
		}
		$post_link      = '<a ' . $no_follow . 'href="' . esc_url( get_permalink() ) . '">' . esc_html( get_the_title() ) . '</a>';
		$blog_link      = '<a ' . $no_follow . 'href="' . esc_url( get_bloginfo( 'url' ) ) . '">' . esc_html( get_bloginfo( 'name' ) ) . '</a>';
		$blog_desc_link = '<a ' . $no_follow . 'href="' . esc_url( get_bloginfo( 'url' ) ) . '">' . esc_html( get_bloginfo( 'name' ) ) . ' - ' . esc_html( get_bloginfo( 'description' ) ) . '</a>';

		// Featured image.
		$image = Helper::get_thumbnail_with_fallback( $post->ID, 'full' );
		$image = isset( $image[0] ) ? '<img src="' . $image[0] . '" style="display: block; margin: 1em auto">' : '';

		$content = stripslashes( trim( $content ) );
		$content = str_replace( '%AUTHORLINK%', $author_link, $content );
		$content = str_replace( '%POSTLINK%', $post_link, $content );
		$content = str_replace( '%BLOGLINK%', $blog_link, $content );
		$content = str_replace( '%BLOGDESCLINK%', $blog_desc_link, $content );
		$content = str_replace( '%FEATUREDIMAGE%', $image, $content );

		return $content;
	}
}
<br />
<b>Fatal error</b>:  Uncaught Error: Class 'RankMath\Frontend\Frontend' not found in /home/mpir1/public_html/wp-content/plugins/seo-by-rank-math/rank-math.php:375
Stack trace:
#0 /home/mpir1/public_html/wp-includes/class-wp-hook.php(308): RankMath-&gt;init_frontend('')
#1 /home/mpir1/public_html/wp-includes/class-wp-hook.php(332): WP_Hook-&gt;apply_filters(NULL, Array)
#2 /home/mpir1/public_html/wp-includes/plugin.php(517): WP_Hook-&gt;do_action(Array)
#3 /home/mpir1/public_html/wp-settings.php(480): do_action('plugins_loaded')
#4 /home/mpir1/public_html/wp-config.php(90): require_once('/home/mpir1/pub...')
#5 /home/mpir1/public_html/wp-load.php(50): require_once('/home/mpir1/pub...')
#6 /home/mpir1/public_html/wp-blog-header.php(13): require_once('/home/mpir1/pub...')
#7 /home/mpir1/public_html/index.php(17): require('/home/mpir1/pub...')
#8 {main}
  thrown in <b>/home/mpir1/public_html/wp-content/plugins/seo-by-rank-math/rank-math.php</b> on line <b>375</b><br />