It's not a T2Laser error, it's your machine (Grbl firmware) that is generating the error message.
I suspect it is a memory fault on the Nano microcontroler, these tend to occur when it heats up and will eventually get worse until it fails to boot.
There are other reasons such as the USB going to sleep, but you should have disabled all power savings (including any BIOS settings related to the USB ports) or electrical interference either from the motors or something else.
There are a couple of tricks that may reduce these errors until you can replace the Nano with a better quality version, on the laser controller window, in the settings / advanced menu you can enable Simple Streaming and/or disable Fail-Safe Mode. Simple Streaming does not use the buffer memory on the Nano so reduces the chances of a memory fault due to a bad block (but it can still happen, and probably will as more blocks fail) and disabling Fail-Safe Mode makes T2Laser ignore the error and try to continue sending, not the best idea and probably won't help as Grbl will just go into a locked status and stop anyway.
You could try a small fan to blow air across the Nano but in my experience this is more of an internal temperature issue on some cheap clones so I doubt this will have much effect. I'm guessing it's one of the EleksMaker boards? The Nano on their later ManaSE boards is total junk and in their wisdom they put the MOSFET under it to generate as much heat as possible to ensure rapid failure!
