[notanote]

That’s the best one of the lot. "Dein Name ist ungültig", "Your name is invalid", written with the informal word for "your".

[rossdavidh]

They're trying to say that you and the server are very close friends, you see? No, no, I get this is not correct, just a joke...

[account42]

Formal pronouns in German are on their way out anyway, including in but not limited to software interfaces.