To remove the head record <link rel="canonical" href="" /> when you are using the WordPress SEO by Yoast plugin, simply insert the following code into your theme's functions.php file before the closing php tag:
// Remove Canonical Link Added By Yoast WordPress SEO Plugin function at_remove_dup_canonical_link() { return false; } add_filter( 'wpseo_canonical', 'at_remove_dup_canonical_link' );
Otherwise, you may encounter indexing problems, for example in Yandex, where many pages will be excluded by the robot due to "The document is non-canonical"