Hello, @laowaiandrew

Can you confirm if only the admin page is not loading or the entire website is now loading for you as well? If you’re using a custom-plugin or rewrite .htaccess rule in order to change the admin page from the standard domain.com/wp-admin I will recommend you to turn of such plugin or temporary comment out the rewrite rules in your .htaccess file.

You can also try to access the admin page with the following link domain.com/wp-login.php

Also, can you share if you’re using Apache or Nginx?

Regards,
Alex

try this before jumping to anything else

if the wp admin login problem is occurring after migration (importing backup file) , enter the user name and password set for the wordpress file which you have imported.