@Eric-Katzfey Issue is mostly resolved. There were two main errors to fix. The first was that the cable that I was using needed to have its RX and TX wires swapped as Vinny pointed out. The second was that Docker Desktop needed to be uninstalled and replaced with only the core Docker CE Engine. After doing this, the HITL seems to be up and running on the alternate Linux computer I tested with. On the original computer, the "Serial port closed error" is no longer present although there does seem to be a graphics issue when attempting to run the Gazebo image with graphics.
[image: 1718148966860-8d0e6ab0-9969-4fb4-853c-4879b46992bf-image.png]
Once this is fixed I think it should be all ready to perform simulations.