If you are unable to access admin area, then you need to update WordPress URLs.
One way to do this is by using wp-config.php file. However, if you do that you will not be able to set the correct address on the settings page. The WordPress URL and Site URL fields will be locked and uneditable.
If you want to fix this, then you should add this code to your functions.php file
update_option( 'siteurl', 'http://example.com' ); update_option( 'home', 'http://example.com' )
NOTE : Don’t forget to replace example.com with your own domain name.
Once you are logged in, you can go to Settings and set the URLs there. After that you should remove the code you added to the functions file, otherwise it will keep updating those URLs any time your site is accessed.