Cannot Sign In to Microsoft 365? 8 Ways to Fix It

You open Word, Outlook, or office.com, type your email and password, and Microsoft 365 refuses to let you in. Maybe the password "stopped working" overnight, maybe a code never arrives, or maybe a yellow banner says something is wrong with your subscription.

Most Microsoft 365 sign-in failures trace back to a small set of causes: a mistyped credential, a forgotten or compromised password, a temporary account lock, stale browser data, a billing problem, or an outdated app. The good news is that each one has a clear, official fix.

Work through the steps below in order. They are arranged quickest and most common first, so you may solve this in under a minute without ever resetting a password.

Check That You Are Entering Your Credentials Correctly

Before assuming the account is broken, rule out a simple typing slip. This is the single most common cause and takes seconds to check.

1.Confirm the email domain is exactly right, for example .com versus .co.uk.
2.Re-check the spelling of the email name itself.
3.Make sure Caps Lock is off when you type the password.
4.If your primary address is not recognized, try an alternative email alias or a phone number attached to the account.

Also confirm you are using the correct account type. A personal Microsoft account and a work or school account are different, and using the wrong one will block sign-in even with a valid password.

For a personal account, this is Microsoft's recommended starting point. The guided tool diagnoses most common sign-in issues for you.

1.Open the "I can't sign in to my Microsoft account" support page.
2.Select the Sign-in Helper button.
3.Enter the email address or mobile phone number you are trying to sign in with.
4.Confirm the details and follow the guided diagnosis.

If you have forgotten which address you use, the Helper can also confirm the correct one. Use it too if you see "account doesn't exist" or "We couldn't find an account with that username," since that message often points to a typo rather than a missing account.

Reset or Recover Your Password

If the password is genuinely forgotten, or if a password you know is correct suddenly stops working (a possible sign the account was compromised), recover it rather than retyping endlessly.

1.Select "Recover your account."
2.Enter your email, phone number, or Skype name.
3.Choose how to receive a security code and select Next.
4.Type the requested information and select "Send code."
5.Enter the security code in the "Verify your identity" field, then select Next.
6.Type a new password in the "New password" field and confirm it in "Re-enter password."

If you still know the current password and simply want to change it, sign in to the Change password page for a personal account. For a work or school account, contact your IT admin or use the Work or school password reset option instead. If recovery returns "We couldn't find an account with that username," use the Contact support button.

Error 400 means the password request could not be processed, usually because you tried too many times in a row, or because of an app, browser, device, or network problem. It is not a password-typo error, so retyping the password makes it worse.

1.At the sign-in prompt, select "Other ways to sign in" and use face, fingerprint, PIN, a security key, a mobile app approval, or an email code instead of the password.
2.Update the app: delete it and reinstall the latest version from Google Play, the Apple App Store, or the Microsoft Store.
3.Try signing in from another phone, tablet, or computer.
4.Change your network; if you are on Wi-Fi, switch to mobile data, or vice versa.

If you have signed in too many times in a row, stop and wait before trying again.

Unlock an Account Locked for Unusual Activity

Microsoft temporarily locks accounts to protect against fraud and abuse, often after too many incorrect password attempts or activity that looks suspicious. You can usually clear it yourself.

1.Sign in at account.microsoft.com to be prompted for a security code.
2.Request the code to any phone number; it does not need to be one associated with your account.
3.Enter the received code to verify.
4.Create a new password if you are prompted to.

If you recently verified by SMS or shared a large number of files, the block typically clears within 24 hours on its own. Repeatedly trying to sign in or requesting more codes can extend the lock, so stop and wait if it persists.

Clear Stale Sessions, Cookies, and Cache in Your Browser

The "we can't sign you in right now" error during sign-in or Office install is usually caused by multiple accounts signed in at once, cached credentials, stale cookies, or a service outage.

1.Check Microsoft's service status dashboard first; if a service is down, wait it out.
2.Fully exit your browser to clear active sessions, then sign in again at office.com/signin.
3.If it persists, open a private or InPrivate window, sign in at office.com/signin, then close the browser.
4.Clear your cookies and browsing history, reopen the browser, and sign in again.

If you are in China or Germany, note that those tenants use separate sign-in endpoints (login.partner.microsoftonline.cn and portal.office.de); the standard office.com/signin will not work for them.

Fix a Subscription or Billing "Account Notice" Banner

A yellow bar reading "ACCOUNT NOTICE. We've run into a problem with your Microsoft 365 subscription" is usually a billing problem (a declined or expired card, or an expired or suspended subscription), not a true sign-in failure. Fix the payment, not the password.

1.Close all Office applications.
2.Go to account.microsoft.com/services, sign in with the associated Microsoft account, review the details under Microsoft 365, and renew if expired; then restart the Office app.
3.If the subscription is active, go to account.microsoft.com/billing/payments and update any payment method showing an error; then restart the Office app.
4.If it persists, run the Microsoft Support and Recovery Assistant activation troubleshooter on the same PC where Office is installed.

As a last resort, deactivate the install, fully uninstall Office, and reinstall it from account.microsoft.com.

On a desktop app that still will not authenticate, let Microsoft's automated troubleshooter take over, then sign back in fresh. These troubleshooters require Windows 10 or higher and must run on the same PC where Office is installed.

1.Start the Get Help app on Windows.
2.In the Search bar, enter "sign in to Microsoft Office."
3.Follow the steps provided.

To sign back in manually, open Word or Excel and select File > Account, then Sign In (in Outlook, select File > Office Account). On a Mac, most apps use File > New from Template... > Sign In, while OneNote uses the OneNote menu > Sign In. On iOS, tap Sign In on the Account screen; on Android, tap Sign In on the Recent screen.

In a managed or corporate setup, a non-browser app may fail because a proxy or firewall blocks Microsoft's endpoints. Confirm general connectivity, then have IT create outbound exceptions for *.microsoftonline.com, *.microsoftonline-p.com, *.sharepoint.com, *.outlook.com, *.lync.com, and osub.microsoft.com on ports 80 and 443. Installing the latest Office and Windows updates also ensures modern authentication is supported.

Frequently Asked Questions

My password is definitely correct but it stopped working. What happened?
A correct password that suddenly fails can mean the account was compromised and the credentials changed by someone else. Recover the account using the password reset flow, then set a new password you control.

I keep getting locked out every time I try. Should I keep attempting?
No. Repeated wrong attempts or repeated code requests can trigger or extend a temporary block, and continued attempts can reset the timer. Stop and wait at least 24 hours, then verify with a security code.

I have not used this account in years and now nothing works. Can I get it back?
If you have not signed in for more than two years, the account may have been permanently deleted and cannot be reopened. In that case, recovery will not succeed.

The verification code never arrives. What can I do?
Follow Microsoft's steps for troubleshooting verification code issues, or add another verification method in your account security info so you can receive the code a different way.

I got an email from "Microsoft Support" offering to reset my account. Is it safe?
No. Microsoft Support agents are not allowed to send password reset links or access and change your account details. Any message claiming to do this is a phishing attempt; ignore it.

Why does it say "we can't sign you in right now" only on this computer?
You likely have multiple accounts signed in, or cached credentials and cookies are interfering. Fully close the browser or use a private window, then sign in again with the single correct account.