network cable

Check:

• Cable for any fraying, breaking, connector damage
• console port for any grime, dust, connector damage
• router settings
• router port for dust, grime, connector damage

It could really be any of them but I hope it's just a bad ethernet cable and it is the most likely.

Hello, I've read your post, and I believe I understand your position. The Xbox Ambassadors are here to help.

Sorry to hear you're having such a rough time getting your internet to work with your Xbox, perhaps I can help you troubleshoot the situation. Might I suggest switching The ether cable for a new one, also reset your modem.

After doing this, might I suggest doing a power cycle on your Xbox. To perform a power cycle, I simply disconnect the Xbox from the main power source for more than 10 seconds, then plug it back in. This is a simple procedure, but does fix most common errors.
Once you plug the power source back in, turn the Xbox on, then you will be automatically taken to an Xbox green screen reset mode. Allow the machine a few moments to correct itself, then it will start up normally.

https://beta.support.xbox.com/help/hardware-network/power/restart-or-power-cycle-console

Above I have included a link that you can copy and paste into a web browser to learn more about this.

Use another cable, if the problem persists it may be due to your router or in the worst case to the port of your console.

Check the back of the router to see if the port you connected it to is lit up.

-double check you plugged in both end properly.

I had they same problem a few years ago, my internet cable worked and then one day it stopped working. I checked it on different devices and it was working so i was quite confused. I looked on the internet and found out that there were different varieties
( which i didn't know) i was using a cat5 ethernet cable which i believe isn't supported anymore. Cat5e and cat6 ethernet cables work for xbox, cat7 cables also work but are abit overkill for xbox use and more expensive. I would recommend cat6 for efficiency
and price.