Firefox logout Woocommerce

Hi,
I have a problem with WooCommerce (My Account page) in Firefox:
When I make some changes to my adress and save the them, Firefox logs WooCommerce automatically out.

How can I prevent logging out?

This only a problem in Firefox.
I have try this steps before:
– Other theme
– Deactivating plugins
– Other hosting
– Orginal template files

Thanks in advance!

http://wordpress.org/plugins/woocommerce/