Please make sure that the laptop is equipped with Thunderbolt 3/USB-C 3.1 Gen 2/USB-C 3.1 Gen 1 port(Supports PD), which supports usb c display transfer.
If it is Thunderbolt 3 laptop, please try to update system BIOS, Thunderbolt 3 driver, Thunderbolt 3 NVM firmware, and graphics (GPU) driver from the system manufacturer.
Ensure sufficient power supply to connect external monitors.
Check the HDMI cable or monitor if can work properly.