Compatibility Report

Name of the game with compatibility issues: Deadside
Steam AppID of the game: 895400

System Information

GPU: GeForce 1060 6gb
Driver/LLVM version: nvidia-driver-440
Kernel version: 5.4
Proton version: 5

I confirm:

that I haven't found an existing compatibility report for this game.
that I have checked whether there are updates for my system available.

Symptoms

After launch, the game shows the main menu with the error:

EasyAntiCheat Error: Failed to create IGameClient instance! Check that the game was run from the correct launcher. Online Play may not be available.

Once you click ok the game exits