Wordpress - Notice: Undefined index: host in /var/www/html/wp-includes/canonical.php on line 445

When I change the url from the database I just put forgot to keep http before the ip address . When I set the http it works fine here.

As an update on this: You can debug this by entering your WordPress Database table named "wp_options" and check for the tables "siteurl" and "home". These should reveal a mistake with your url (often http:// or https:// is not copied correctly).

This is a bug in WordPress, scheduled for fix in v5.0: https://core.trac.wordpress.org/ticket/34353