Wordpress broken after domain name change

Question

I configured my Wordpress site to use a new domain name. I'm still using the same hosting provider. I have also set-up the old domain to redirect to the new one. Now, the thing I want to achieve is that I want to remove, from the site, all references to the old domain. However, whenever I point my browser to

new_domain.com/admin

it gets redirected to

https://old_domain.com/wp-login.php?redirect_to=https%3A%2F%2Fold_domain.com%2Fwp-admin%2F&reauth=1

If I point my browser to

old_domain.com/wp-login

it thinks that I'm requesting files in a directory named /wp-login and so gives me "Page not found" error of my site. But if I do

old_domain.com/wp-login.php

it displays the login form but on submit, I get redirected to

https://old_domain.com/wp-login.php?wpe-login=true

And finally, when I login, the url changes to

https://old_domain.com/wp-admin/

The other problem is that the theme is completely broken. I've inspected the html source whose <link> and <script> tags call resources from old_domain.com/path/to/resource/

I have tried all the solutions there are out there. Among those are:

1. changing the site and wordpress url from the dashboard settings.
2. applying search and replace all instances of https://old_domain.com to http://new_domain.com in the database.
3. trying the define( 'RELOCATE', true ); method; it sets the wordpress url to http://old_domain.com
4. in here When moving a WP site, why does wp-admin redirect to old site?, I found these define('WP_HOME', 'http://' . $_SERVER['SERVER_NAME']); define('WP_SITEURL', WP_HOME . '/');. Applied them thinking this would fix it as I'm not hard-coding any urls. But these, too, set both the site and wordpress url to http://old_domain.com

Can anyone point me in the right direction?

I didn't need to move the database or the Wordpress installation around as I didn't change hosting provider. So, as a last resort, would it be a good idea to delete the wordpress installation and reinstall it with all the themes in place?

Answer 1

I'd use a Search/Replace plugin (I like "Better Search and Replace") to change all instances of 'olddomain' to 'newdomain'.

Then I would look at the wp-options table to ensure the new URL is in there (in two places). I'd remove any URL-based settings in the wp0config.php file. (I never change those.)

I'd also check the htaccess file in the new site's root folder to ensure that it isn't doing any redirects or rewrites to the old URL.

Then, using a new browser instance (a private one insures caching/cookies aren't an issue), I'd try the new URL. If needed, use the browser Developer Tools (usually F12; or right-click and 'Inspect') and look at the Network tab to ensure all requests are for the new URL