The lidars occupies 192.168.1.1 as its broadcast address

[jarekkt]

This is nasty surprise. Partially documented in manual:

Set the IP address of your computer to static IP address. Note that the static IP address of your
computer should be 192.168.1.X. X can be set to any number between 2 to 233 and should be
different from the IP address of the Livox Mid series LiDAR sensor set in Step 2.

The broadcast messages from will use the address - so if you have already any other computer ( and this address is usually occupied by router) you will get ROS2 driver confused - it will be getting packages from your router and disconnecting the lidar ( mess in hearbeat protocol).

This is nasty as it does not affect the livox viewer ( which can filter out packages properly), but not ROS2 driver.

I would recommend both fixing the driver ( to deal with it) and changing the address to something else ( like 192.168.1.255 )