error customize theme

Your site is trying to load a file named admin.php from your WordPress installation folder, wordpress.

But the official WordPress software downloadable from www.ads-software.com doesn’t have any such file at all: https://core.trac.www.ads-software.com/browser/tags/6.3.1/src

I see you mentioned an error, but you didn’t provide specific details about the error or what you’d like to customize. To assist you effectively, please provide more information about the error you’re encountering and what customization you’re looking for. This way, I can offer more targeted assistance.

Please see George’s response, above. If the errors you pasted are correct, then it’s likely you’ve been hacked.

Get a fresh cup of coffee, take a deep breath and carefully follow this guide. When you’re done, you may want to implement some (if not all) of the recommended security measures

https://www.ads-software.com/support/article/faq-my-site-was-hacked/

https://www.ads-software.com/support/article/hardening-wordpress/

If you’re unable to clean your site(s) successfully, there are reputable organizations that can clean your sites for you. Sucuri and Wordfence are a couple.