unsaved data

On the website we have created several users and recently we have had some technical problems. (we moved to Guttengerg)
Here’s what happens:
• I create a user with user name, last name and password from the backend and assign him a role.
• verify the user in another browser and it works
• I exit from backend
• I try to log in again with the credentials that before worked but don’t work anymore
• I enter again into backend and I realize that the user is there but there is no more information about name, surname and role. The assigned role is “none”

I also tried a test from the registration form in Reserved Area, with the user registration procedure. At the beginning it works, then if I leave the site and try to return, it doesn’t work anymore. In fact, if I enter in the backend as administrator to control the user, the subscriber role has changed to “none”.

The page I need help with: [log in to see the link]