If your other RokuTVs are working fine, and 0 networks are showing up on the problem TCL RokuTV, appears that the NIC (network interface card) is most likely the issue. (This is basically the wi-fi chip inside the TV). Without a valid MAC address, the router is at a loss to send/receive data since it is basically an identifier.
Of course, this NIC is only needed if using a wi-fi connection. If you can use an ethernet connection (RJ45 network cable wired to router LAN port), then TV will again operate properly since it bypasses need for wi-fi chip. (select Wired Connection)
If you can't use a wired connection, then some of the fixes include verifying that the NIC is properly grounded (sometimes adding additional ground wire) and that the solder connections of the wifi chip are secure to the board. Unless you are able/willing to disassemble TV and do some relatively simple soldering, Another indicator of bad grounding would be to unplug TV for an extended amount of time (10-15 min) and then attempt to reconnect. I doubt you will discover it to be a simple miscommunication between your router and TV. But there is always the chance.
You can try to setup a new connection. Navigate on RokuTV to Settings...System...Advanced System Settings...Network Connection..Reset..Reset Connection
Before trying to reconnect, you then enter router settings and release the assigned IP from the DHCP server. (your IP can be found at RokuTV Settings...System...About (Same place you are seeing MAC address of 0). This is assuming IP is still assigned and just MAC address assignment is lost.
Then reboot both router and RokuTV and cross fingers. The only other option is to do a factory reset of your TV and again cross fingers. Realistically though, I would be prepared to accept a hardware failure/grounding issue in need of a manual fix/repair as culprit over a simple connection correction. I do remember a youtube or other video that showed someone doing the ground wire trick/repair I will edit this post with a link if I can find it. Maybe can be of of can help to you or others.
Hope that helps get you going. Post back with any updates or need additional help.
EDIT...not the video, but here is a simple walkthrough..... https://www.instructables.com/Fix-Bad-Mac-Address-on-ROKU-TV/
Additionally, you can try such a fix with just tapes and glues or liquid solder if so inclined with the stranded ground wire. You don't necessarily need a soldering iron.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102
