I found the following issue. I made a Live Timing for my league which gets the data via the Web UI port from the dedicated server. My server is configured that no skin transfer is allowed. I noticed that if a player joins the server which has a lose skin for the car the web ui port stops sending data (isn't reachable anymore). As soon as the player leaves the server the web ui port is working again. By lose skin I meen that the player used the car to generate his custom skin and has a alt...dds in his settings folder for this car.