Lan - join kick

I have a Mojang.com Acc. i must login with me email and password.

so i go in offline mode and open a single game to lan.
no user can connecting look @picture. me eMail is 25 long, allowed 16.

The problem is that I do with my own acc. not twice allowed on a server (LAN).

So I turned off my internet, and I thought to myself I'm in offline-mode as purely because I do not have the same name but the email my name in a offline-mode.