Xbox one Update Preview Unenroll second hand xbox

According to support.xbox.com/en-US/xbox-one/console/how-to-leave-xbox-one-update-preview-program Support
article, the previous owner should have unenrolled the console before giving it away or selling it. You may have to contact Xbox Support now to have a Microsoft agent help you unenroll it if you cannot do it yourself by the Xbox Insider app.

Good luck!

I would suggest that you keep trying to
unenroll. Ensure you have a stable connection to the internet, and give the console a simple
power cycle and attempt to unenroll again.

After successfully unenrolling, you should be prompted to perform a system update your console (reverts to the current public release).

It is not possible to unenroll during a preview wave.

At the moment the October preview wave is already rolling. So you will have to wait until the October update gets public. You will be unenrolled then and will not get any more preview updates.

Are you in the preview program by any chance?

I had this the other day after an update. When I checked, I had been in the preview program. Unenrolling fixed it. Best thing to do would be to unenrol from the program and see if the problem persists. Bare in mind that after you unenrol, you will have to
run through the initial setup of your xbox again.

It sounds like the original xbox one that updates very often is enrolled in the insiders program where you get preview updates before others. If you want to unenroll please open the preview app and select the option to unenroll this xbox from the program
and the next update will be the regular public build.

For more info on the insiders program:
https://support.xbox.com/en-US/xbox-one/console/xbox-insider-program

For support in the insiders program please post here:
https://www.reddit.com/r/xboxinsiders/

-------------

About the network error, if you turn off the console and unplug it for 30 seconds and reboot does it still happen? Can you try the Network connection test in Settings > Network to be sure it doesn't say "hardware problem" after that reboot?