doesn't work

Do you by chance have two-factor authentication enabled on your gmail account? If that’s the case, you would need to create an application-specific password.

As another guess, if you had loaded the widget first, then authenticated, it might not release the cache for 15 minutes.

There’s a good chance this might be resolved for you in version 1.1 that I released tonight.

It adds server presets for Gmail, Yahoo, Outlook, iCloud, and AOL, so there’s a good chance your server settings will be correct by default.

The plugin also validates your login credentials on the settings page and reports any errors with clearer notices.

Hope that helps. If your problem still persists, please let me know if you get any new messages on the settings page. (And what email host you’re using!)