Please check if by chance the option of the headset in the Steelseries Engine 3 is active: "Turn headset off after inactive for:".

Don't know what that means in German!

But switching off after 30 seconds is rather unusual. Is the battery charged and is the connection to the PC, PS or mobile available?

The option can be found under Configuration / Settings and is called "Headset Auto Power Off" in German and a drop-down menu with the selection "Never" or 10min to 50min.