Do you mean after you log in or when you just visit the page?
When I visit http://cnktagency.com/wp-login.php - the URL does not change.
When I visit http://cnktagency.com/wp-admin/ I get redirected to the URL you mention.
Perhaps clear you cookies or try a different browser and try and visit http://cnktagency.com/wp-login.php again.
If that doesn't help I would probably try and reinstall WordPress manually via FTP - https://codex.wordpress.org/Updating_WordPress#Manual_Update