So, it just stopped communicating via USB? I would look to the supplier for additional diagnostic procedures to ensure you have a good control board with working USB port.
You also say you can not connect via Ethernet. Please describe what you tried, what settings were used, and the results. The details matter when looking for feedback. 
This is worth review: How do I connect a Ruida controller with Ethernet?
Another test to see if this is a LightBurn software issue, can you connect using RDWorks over USB? Additionally, you can roll back to an Older Version (9.20 or earlier) to see if you can connect consistently.