Lenovo Laptop: external screens suddenly not recognized

Hi!

This morning my Lenovo X1 gen8 could not detect an external display via HDMI. Another display, connected via USB-C, is also not detected (even though the built-in USB-hub works with mouse/keyboard).
Yesterday evening everything worked fine.

xrandr does not even list the external displays. The only thing I tried so far, was to update the kernel but it did not help (restarting the machine did also nothing).

Would you have any pointers on how to start looking into this problem?

Thanks!

It works now for some reason. I checked the BIOS settings but could not find anything suspicious. The only thing I enabled was the USB charging while in the laptop is powered off and not connected to a power supply but I would be surprised if that fixed it.