Login Failed: Unable to initialize Windows Gaming Services!

check for updates in windows store, i had a gaming services update today.

If theres no update i would contact the support team

If your save data is missing or if the game is unable to synchronize your data, try signing in to the Xbox app and then restarting your device to recover the account data. Gear of War: Ultimate Edition services login failed, access to online multiplayer
is not available. You are not connected to Xbox Live.

I did try this a week ago and it didn't work for me.

I just gave it another try and it still doesn't work.

Authentication from within games still fails, for example in Grounded: Xbox Live popup appears, I click on my account and the login fails with the above error code.

Login in every other Microsoft service works without a problem: Windows, Office 365, Outlook, and even this damn Xbox app.

it will initially use your windows login credentials, if these are different then you would need to login with the correct account, if your app is not working reset it or check the windows store for app updates.