Can't remove XBOX device on Microsoft account

Hello Vladimir, sorry to hear you're having trouble removing the console.

I've not seen this particular error before. Perhaps try using a different browser to see if you still have the same issue. If you do though then I would recommend contacting a Microsoft Advocate via https://account.microsoft.com/contact-us for more help.

Hi Laly,

Thanks for getting back to us. Currently, we don't have a way to choose to remove the account from all your devices. If you would like to remove your account from any device you would have to
manually go and choose to remove the account through the device.

To Remove your Microsoft account from your devices:

Go to Settings
> Accounts > Your account

Tap or click Disconnect my Microsoft account, and restart the device



One thing we have available is to remove the devices from your Microsoft account when you
sign in through our Device section online, (ex; if you registered an Xbox One S on your account it will show up under your devices section)this will allow you to
remove the device from the account but this doesn't remove your account from the device.

Sorry for the inconvenience, hope this information helps.

Manage devices used with your Microsoft account

Manage devices used with your Microsoft account
Applies to: Microsoft StoreMicrosoft accountWindows 10

Add a device

• You need to add a device to your Microsoft account before it's listed in your devices. Here's how you can add a device:
  
  • Sign in to your Microsoft account on an Xbox or PC.
  • Download an app or game from the Microsoft Store .
  • Go to account.microsoft.com/devices, select Don't see your device?, then follow the instructions.
  • On an iOS device: Download Microsoft Edge from the Apple App Store and sign in with your Microsoft account.
  • On an Android device: Download Microsoft Edge, Microsoft Launcher, or Your Phone Companion from the Google Play Store and sign in with your Microsoft account.
  • MacOS devices can't be added at this time.

Rename a device

• Change the default name of your device so you can quickly identify it in your Microsoft account. When you want to download an app or game to another device, you'll be able to find the device using its new name.
• To rename a PC:
  
  • Select Start > Settings > System > About.
  • Select Rename this PC.
  • Enter a new name and select Next. You may be asked to sign in.
  • Select Restart now or Restart later.
• To rename an Xbox:
  
  • Select Settings > System > Console info > Name.
  • Enter the new name and select Enter.
  • Restart your Xbox.

Remove a device

• Manage your device list
• If you don't use a device but it still appears in your devices list, here's how to remove it:
  
  • Go to account.microsoft.com/devices, sign in, and find the device you want to remove.
  • Select Show details to see info for that device.
  • Under your device's name, select More actions > Remove.
  • Review your device details, select the check box, I'm ready to remove this device, then select Remove.
• If you want to remove a device for a child in your family, have your child sign into account.microsoft.com/devices, then follow the same instructions.
• Unlink a device from Microsoft Store
• If you can't download from the Microsoft Store, you may have reached your device limit. Manage your limit by removing devices you don't use or no longer have access to. To unlink a device:
  
  • Sign in with your Microsoft account at account.microsoft.com/devices/content.
  • Find the device you want to remove and select Unlink.
  • Review your device details and select Unlink.
• Once you unlink a device, it won't count towards your device limit. If you haven't reached the limit, and download an app or game on this device later, it will count towards your device limit again.

Find or fix a device

If you sign into your Microsoft account, you can find a missing device, schedule a repair, get support for a device, and more.

• To find or fix a device:
  
  • Sign in to account.microsoft.com/devices.
  • On the Devices page, select Show details for the device you want to find or fix.
  • Either select Find my device or, under Windows Defender settings, select Show details and check for any security issues.
• If you're having trouble downloading or updating apps on any of your devices, see Fix problems with apps from Microsoft Store or I
  can't find or install an app from Microsoft Store.

A Microsoft account and Xbox account are essentially the same thing. You can't remove an Xbox account from a Microsoft account

Ive just had a look go to microsoft account manage devices remove xboxes