The problem I have is in simple theory, but I have not found a way to solve it.
I can access FB with unity, post, view and use the information I need, all that part works well, all the information I use is stored in a local file on the phone.
When you delete the application (uninstall it) and reinstall it and try to log in again I get an error, since the session through the application has already been allowed.
Someone could help me say how I can "re-authenticate" the FB session.
Update 14 Jul. at 20:16
The error I had was that it told me that the "Key Hashes" did not match with any application, the solution to that problem is quite simple, just take the hash key that returned the app and add it in the "Key" Hashes "of FB, after that the problem was solved in all the devices.
The only "problem" is to distinguish between the uppercase "I" and the lower "L".
But they should only take that "Key Hash" and with that it is solved, apparently only the "Key Hash" of unity is taken care of to access the first time, and the rest is required of the app.