Step 1: Click "Configuration Files" button on the control panel.
Step 2: Click "GameUserSettings.ini" -> [ Configuration Editor ] -> Search For "serverPVE" and select "Disabled".
Step 3: Click Save,
Step 4: Click "Game.ini" -> [ Configuration Editor ] -> Search For "bAutoPvETimer" and select "Disabled".
Step 5: Click Save.
Step 6: Restart Your Server.

Your server will now be Player vs Player vs Environment.
serverPVE

If you would like to purchase an Ark server click here