cannot get usb c ethernet adapter connected to my m1 imac apple tech swears it will work with my thunderbolt 4 port but it wont connect, any advice

This one, right? -> The Belkin USB-C to Gigabit Ethernet Adapter - Apple

I noticed in the description that it says "Perfect for MacBook with USB-C port or MacBook Pro with Thunderbolt 3 (USB-C) ports," - it does not mention Thunderbolt 4. It has been out for a few years already and may not be ready for prime time with the new TB4 ports. I have seen other reports of issues with this adapter. If possible, return it for exchange.

Does the system report from About this Mac show the usb c to Ethernet show up under usb tab?

If yes, then

goto system prefs in Menu bar in finder and goto networks, does it show any Ethernet connections active ?

if so try tapping the i with a circle around it?

in the window that appears, does it show an ip address of 169.X.X.X ?

if so that says a router is not handing out the ip address as it should provided your are not using a static ip address, which most don’t.

Try requesting for another dhcp request from router in the window which shows ip address.

The router should respond in less that 10 secs. If it still says a 169.X.X.X address the router should be rebooted and tried again.

You could also use the terminal from Applications/utilities to issue this command which will show all Ethernet connections with it status on up and running with lots of detail.

user% ifconfig -a

look for Ethernet output that states “up” and “active” with an ip address of something other than the first three digits being “169”

a call to Apple support can be utilized to help resolve this issue quickly by calling 1-800-MY-APPLE

Do you using any of the following:

• Cleaning app(s)

• Antivirus app(s)

• VPN

• Third party security apps

• Third party "maintenance" apps

If the answer is no to all of the above please do the following:

It will help us get a good idea of what is causing your problem if you provide a report of your system, that way we do not have to play 20 questions with you. The report we are requesting does NOT provide any personal information and is extremely safe to use. Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again. 

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click How to use the Add Text Feature When Post… - Apple Community

Try another adapter.

Then I'd recommend that you give AppleCare a call to see what the issue is. Use the following link to find the correct phone number for your area: AppleCare Contact Info

Okay, please post your EtreCheck report.

bwalk1963 wrote:

" ... and they say it works ..."

But it obviously doesn't.

If you have spent that much time on the phone with Apple Support and nothing gets it working, that's all the more conclusive evidence that it's not working despite what they claim about the dongle.

If your M1 iMac is still under warranty or you have AppleCare Coverage, start a support ticket -> My Support - Official Apple Support or set up an appointment with the Genius Bar at the closest Apple Store.

Exactly what usb c ethernet adapter is this?