How ot fix DNS Check Failed Domain name problems
Code for htaccess
# 301 --- https://yourdomain.com => https://www.yourdomain.com
RewriteCond %{HTTP_HOST} ^yourdomain.com$
RewriteRule ^$ https://www.yourdomain.com/? [L,R=301]Code for wp-config.php
define('WP_HOME', 'https://www.yourdomain.com');
define('WP_SITEURL','https://www.yourdomain.com');