Ruh roh! It looks as though there is a cracking down on people using third party Metro Exodus keys.
These keys have been obtained illegally from the factory where physical key printing had taken place prior to the announcement of exclusivity with Epic Games, due to the criminal nature of these keys, all unlicensed keys have been deactivated and activation / download of Metro Exodus without the executable file is no longer possible. In addition, the software will be removed from the Steam library of any players using an unauthorised code. The keys being sold on this platform are stolen goods, and are therefore illegal.
