Have you authorised the dock as a Thunderbolt device in the operating system? In Windows you can find this in the settings, also in Ubuntu. There is also an option in the bios that automatically authorises all devices, but this is switched off by default for security reasons.

Well, that's a good question, but unfortunately I don't have an answer. Our laptop runs on it without any problems, but simply with an external ASUS monitor. With your problem, I would rather assume drivers, settings, etc. on the laptop... Greetings, Michael