I setup a LAMP server on my new laptop and downloaded a website from the live server to my local machine. Everything appears to be working, but I can't login, when I go to http://localhost/mysite/wp-login.php and enter the correct details, it just redirects back to wp-login.php without actually logging in.
I'm using a new WordPress install on my local machine so it's a new wp-config file.
I made sure the site URL is correct in wp_options, I made sure the username and password is correct, I tried downloading the .htaccess file from the live server, I tried defining WP_HOME and WP_SITEURL in the wp-config.php file. I tried changing browser to Chrome (which has no extensions and no cookies or history, I never use Chrome).
I tried adding:
define('FORCE_SSL_ADMIN', false);
to wp-config.php. I tried deleting all plugins.
I don't know what else to try, or how to diagnose the problem.