We have not had reports of any LightBurn issues with 9.19 over Ethernet with this controller, so let’s check a few things.
For our clarity, how are you sending the job, by using the ‘Start’ button, or hitting ‘Send’, naming the file and running from the controller?
Does the controller have a lot of files stored on it? We have seen the Ruida act up when reaching its capacity. Clear files you do not need to ensure room for the transfer. In cases where the controller is close to full, they can be somewhat unstable.
Do you get these same results when testing from RDWorks? This would help isolate the issue being something in Software.
Make sure that the network cable is known to be good, well seated in the sockets at either end, and not running next to anything like a compressor motor or A/C fan.
On some setups, there is a short extension cable in the machine that connects the controller inside to a plug on the case, worth checking. Rare, but we have seen reports of those failing. If yours has a similar configuration, you could try opening the side panel to expose the main controller box inside (the white, smooth plastic box with lots of wires going in). On one end you’ll see PC-USB, UDisk, and Ethernet ports labeled - try plugging directly into the Ethernet port there, and if that works that could be the problem.
Let’s start with this, and update as you can.