Sending, receiving, and organizing email in Outlook.com
Hello,
Make sure you add a new recovery email address before deleting the older one.
Go to the 'Security Settings page' of your Microsoft Account here: https://account.live.com/proofs/Manage
Select 'Add another way to sign in to your account'.
Add a new recovery email address or set up Authenticator to verify your identity.
You can then remove the Closed email address from the security settings page of your Microsoft account.
(This is how the page looks. Make sure you are also on the same page where you remove your closed email address)