Same problem here. About three days ago our 55 inch TV (UN55NU8000FXZA) suddenly stopped connecting to WiFi. Mac address and everything shows all 0s. Works fine wired. Won't see anything wireless. Called support. Tried unplugging for 15 minutes. Tried rebooting with the remote. Tried resetting. Nothing they suggested worked. Samsung shows no firmware update (the page says that the information for the NU8000 series in unavailable) So, after having the screen replaced under warrantee (black lines across it) we now have no wifi. I think we got a lemon. And the warantee expired.
It's looking like my only option is to order the WiFi module and replace it myself. I have to assume that the module went bad, too.
I've tried every thing on the net, however nothing worked but one thing.....unplug the power cord from the back of the tv......this thing reset some settings on the TV......then try to vacuum the ventilation vents on the back of the TV since it might be clogged and causing the overheat, which is according to many the main reason for the wifi problem.....turning on and off, resetting...and other things will give a temperoray solution....but eventually it will stop working ouy....good luck everyone....I hope it will work out for you.
Well, after posting my post by two days...it stopped working for me again.....so I decided to do it the hard way....so I've unscrewed the back of the tv...and I've discovered that the modem wire is made of cheap material.....and it was lose as well....therefore, I've done the regular thing by cleaning it with alchohol.....plug it back.... it was of course for both sides of the wire......and voala.....its been working like a charm since then......however, if you are not experienced with electric work, I advice you to see professional or at least to watch several videos on youtube to see the modem place and its wire.....good luck....and one more thing....the quality of the TV is really bad.....so I wouldnt recommend it to anyone!!!
We popped the back off, got the module part number, ordered the part and 2 days later unplugged the old and plugged in the new. Cost of repair - $15 for the WiFi module. All we had to do was unscrew the one screw holding the bracket and unplug it. It was that simple. Working like new again. 🤷
Solving the Invalid MAC address error. This was a real experience with Samsung. DISH does their service. The problem was a physical failure of a component in the TV that does the connecting to Wi-FI. After going through hoops and chats and what not finally found a way to get a tech to the house to fix the problem after over 6 hours of trying to correct the settings. Could have been one of two things. Turned out to be the cheaper of the two. (The other was about $300 for the part) A 2inch by 4inch circuit board. $100 for the diagnosis or to just get someone to come to look at it, $45 or so for the part. add in labor and tax about $271 total cost. The guy knew exactly what to do. Trying to get him here was the issue.