Managing personal Outlook.com account settings, security, and privacy
Hi, thanks for reaching out. First, do you recall if your gamertag was ever set up with a different email or phone number?
Microsoft requires you to sign in using the exact email linked to that Xbox profile. Check the account you are logged into at account.microsoft.com to confirm the email in “Your info”. If it is not the correct one, use Microsoft’s Account Recovery form and provide any details you remember like old passwords or a phone number. Microsoft support will not restore access using a gamertag alone, so recovery info is needed.