Wuisma found a solution
It's not a cookie problem
Hi,
first of all sorry for my english, i think that, in some cases, is a problem whith the cookies and the domain configuration (in SEO & URLs).
If you observe the cookies using the developer tools of chorme, for example, you can see cookies with two diferents domains with www and without www, so i tray to erase the www. in the domains in SEO & URLs. Now i have only one domian for the cookies and it seem to work without problems.