Have you tried contacting TCL support yet to inquire further? I'd suggest starting there to see what options or suggestions they can provide. Each Roku TV manufacturer provides direct support for their products running the Roku OS.
Yesterday I performed factory reset on my TCL Roku TV 75S535. Then it won’t active or update anymore. Before that I was using Netflix and YouTube so I think my network works just fine. I tried WiFi and RJ45 but they all get the same result “Error 008”
We recommend rebooting both your wireless router and your Roku device.
I'd also recommend trying to connect your device to an alternate network, such as a mobile hotspot, to see if you can resolve the issue you are seeing. Then once your Roku TV has been setup, try switching back to your home wireless network to see if you are still experiencing the issue.
I saw that on my 55S20 TCL Roku TV as well, and when we tried to do a firmware update on tvupdate.roku.com it actually told me that it was an Unrecognizeable Model.
I'm thinking Roku just didn't update their database here or something. Just waiting on the manufacturer who said "they (and Roku) were aware of this and working on a resolution". Just gotta play the waiting game then.
Will send an update to this once they do get back to me.