So you’ve just installed the WP SUPER CACHE plugin and now you’re finding that in Chrome and / or Firefoxbrowsers users cannot login. Your behaviour might look something like returning to the home page. If you have error logs, you can see that users have the right credentials (i.e. they are logging in with the correct username and password).
This was a recent problem for me on a large site. I had recently tried and uninstalled W3 TOTAL CACHE. The solution came down to one line of code in my wp-config.php file. wp-config.php is found in the root folder of your WordPress installation.
W3 TOTAL CACHE adds two lines of code, that it does not remove on uninstall. They are generally found at the top of the config file. And they are marked as added by W3 TOTAL CACHE.
Remove the line
define('COOKIE_DOMAIN', 'www.olddomain.com'); // Added by W3 Total Cache
Other solutions that might be helpful can be found on this page at Stack overflow: http://stackoverflow.com/questions/20941328/wordpress-admin-login-cookies-blocked-error-after-moving-servers
