Why can’t sign in to Azure

Microsoft Authenticator treats "work or school" accounts (like your edu/Azure AD account) and "personal Microsoft" accounts (outlook.com, hotmail.com, or a personal account with a custom domain) as fundamentally different entries, even though they live in the same app. A work/school account, once registered for MFA on that tenant, shows a rotating 6-digit TOTP code and can receive push notifications and it's tied specifically to that tenant's registration, not to any email alias. A personal Microsoft account instead shows an 8-digit code, which isn't a standard TOTP at all it's the passwordless sign-in code used for personal Microsoft account recovery flows.

So what likely happened: changing your alias touched your personal Microsoft account, and somewhere in that process the app either dropped or never properly kept the separate work/school registration for your edu account. That's why you're now only seeing the personal account's 8-digit code the school account's registration is effectively gone from the app, which is also why no push notification ever arrives (there's nothing on the tenant side to push to, or the binding between the app and the tenant registration is broken). Disabling MFA on your personal profile and reinstalling the app wouldn't touch this, because that's a different account object entirely.

The core problem is that this isn't something fixable from your end or from a chatbot: only your school's Azure AD/Entra ID tenant admin can reset your MFA registration, because self-service MFA reset almost always requires... MFA. That's the loop you're stuck in. A few things worth trying:

1. Check the Authenticator app itself under Settings for a list of accounts, and confirm whether the school account entry still exists at all (it may show a different name/icon than your personal one). If it's missing, there's nothing to receive a push — it needs to be re-added from scratch, which again requires an admin to unlock the process.
2. On the school's sign-in page, look for "I can't use my Microsoft Authenticator app right now" or "Sign in another way" — if any backup method (phone call, SMS, security questions) was ever registered on that account, it'll show up there and can bypass the broken app link entirely.
3. Stop going through the automated support bot and go directly to a human at your school's IT helpdesk — by phone, in-person at the IT service desk, or via a ticket explicitly marked for account/MFA lockout. Automated loops for MFA resets are usually designed to filter out exactly this kind of edge case rather than solve it. Have your student/staff ID, full name, and any alternate contact info on file ready, since they'll need to verify your identity manually before resetting your authentication methods in Entra ID.
4. Once you're back in, add the school account to Authenticator again via Security info → Add sign-in method, scan the QR code fresh, and also register a backup method (phone number or backup codes) so a single broken registration can't lock you out again. It's also worth keeping the personal and school entries visually distinct in the app going forward, since alias changes on the personal side seem to be what tripped this.