Unfortunately, Kerio's Personal Firewall has been known to disrupt Yahoo! Mail's ability to function properly.

For Yahoo! Mail to work on your system, you'll need to make it one of KPF's site exceptions.

Here's how to do it:

1. Double-click the Kerio Personal Firewall icon to open the firewall configuration.
2. Click the Web tab on the left.
3. In the Site Exceptions tab, click the "Add" button, and enter *.mail.yahoo.com for the www server address.
4. Click "OK".
5. Click "OK" to save and close the configuration.

You can now use Yahoo! Mail Beta while using Kerio's Personal Firewall.