I tried to start the game from steam, but at the start, I get an authentication error.
If anyone can help, thx.
The Steam client is online, internet connection is ok, but can't start it.
Try out the following options which reportedly helped other players with this issue in the past:
Restart Steam and then check if the game runs
Run Steam in administrator mode then launch the game
Launch the game from the game's library
Launch the game as an administrator