No longer able to sign into any Xbox app or game bar since changing alias email

I'm Samy an independent advisor and I'll be helping you

Close the Xbox app and open the Xbox Companion app, if you don't have this app installed, download the app using the Microsoft Store on your Windows.
Then open the app, log in with your account, open the Xbox app and see if that resolves the issue.

Hi Ememn,

Thanks for reaching out to the forums. We see you want to change emails. Unfortunately, you will not be able to with them emails. As they are both Microsoft domain emails. Also, if you remove an email, you will not be able to use it any longer. Here is a
guide for
changing primary alias for further information.

Warning When removing an email alias that’s a Microsoft domain (such as @Outlook.com, @Live.com, or @Hotmail.com), that email is completely deleted from our systems and can no longer be used to send or receive emails. It won’t be available
for use again as an alias on another account. Microsoft does not recycle email addresses, so it may not be reclaimed at a future time.

Hope this helps.

Brad

Hi there Oliver,

Thanks for reaching out! If you change the primary alias the email that was ther will not be active since it will be removed from the account.

Take a look at XBF Javier post, " To answer your question, we'll provide the
How to change the email address associated with your Microsoft account
which has this stated within the page:

Remove the email address you no longer want to use to sign in

Note: If you choose to remove an alias that uses a Microsoft domain such as @hotmail.com, @outlook.com, or @live.com, that alias will be completely deleted and will not be available to sign in to any Microsoft
services.

To remove the email address you no longer use to sign in to your account, select Remove next to that alias on the Manage your account aliases page, and then follow the instructions provided.

Important Do not remove this email address if you still want to use it to send and receive email messages.

Hope this helps.

I'm not entirely sure if this is possible to do. You might be able to add a new alias (Alias B) to your account and make that new alias the primary account (Alias A). Then create another email address(Alias C) and add your current email (Alias A) as a primary
alias to that account

But since you can't transfer data from one account to another I'm guessing it's not something that's possible

You can find more information regarding what I'm talking about here:
https://beta.support.xbox.com/help/Account-Profile/manage-account/change-email-sign-in-for-microsoft-account

[i][b]Warning[/b] When removing an email alias that’s a Microsoft domain (such as @Outlook.com, @Live.com, or @Hotmail.com), that email is completely deleted from our systems and can no
 longer be used to send or receive emails. It won’t be available for use again as an alias on another account. Microsoft does not recycle email addresses, so it may not be reclaimed at a future time.
[/i]

Hi there, Zanas0614!

Yes, you can change your email address without any trouble. And to protect the old email, do not delete it from the account.

And this is the only way when it comes to add a new email/alias to an account.

Once you have added the new email/ alias and set it as the primary email you will be using that email when signing into your account.

Therefore, your email will change but everything on the account remains. All of your games, subscriptions and apps will be on the account.