How to fix Microsoft 365 login problems

Where to sign in to Microsoft 365

The quickest way into Microsoft 365 is m365.cloud.microsoft. Sign in with your full work email address and password, then approve the sign-in on your phone if you use multi-factor authentication. If that page won't load, login.microsoftonline.com takes you to the same Microsoft sign-in screen. IT admins manage accounts at admin.microsoft.com.

If you still can't get in, the fixes below are in the order we'd try them. Most login problems are solved in the first three steps.

Quick fixes to try first

1. Check the email address. Use your full work address, such as name@yourcompany.co.uk, not a nickname or personal address.
2. Check the account type. If Microsoft asks whether you mean a work or school account or a personal account, choose work or school.
3. Reset your password. Select Forgot my password on the sign-in screen. If your organisation hasn't turned on self-service reset, your IT team or provider can reset it for you.
4. Wait if you're locked out. Microsoft locks an account for a short time after repeated wrong passwords, and the lock gets longer if attempts continue. Stop trying for a while rather than guessing again. Resetting your password with Forgot my password also clears the lock.
5. Try a private window. Open an incognito or InPrivate window, or a different browser. This rules out old saved sign-ins and browser extensions.
6. Check your connection. Try another network, or turn off a VPN if you use one.

Multi-factor authentication problems

Many failed sign-ins are about the second step, not the password. Common causes:

• New phone. The Microsoft Authenticator app doesn't move across on its own. Your IT team can reset your sign-in methods so you can register the new phone.
• No prompt arriving. Open the Authenticator app directly and check for a pending request, and make sure notifications are allowed.
• Prompts you didn't ask for. Deny them and tell your IT team straight away. Repeated unexpected prompts can mean someone else has your password.

When the whole team can't sign in

If several people are affected at once, the problem is unlikely to be anyone's password. An administrator should:

• Check Health then Service health in the Microsoft 365 admin centre for a Microsoft outage.
• Review recent changes to conditional access or sign-in policies.
• Check the affected accounts still have an active licence and haven't been blocked from signing in.

Problems in the apps rather than the browser

If the browser works but Outlook, Teams or the mobile app keeps asking for a password:

• Update the app to the latest version.
• Sign out of the app completely, close it, then sign back in.
• On Windows, remove old work accounts under Settings then Accounts then Access work or school, then add yours again.
• On a phone, check the operating system is still supported by the app.

Stopping login problems coming back

• Turn on self-service password reset so people can fix forgotten passwords themselves.
• Ask everyone to register more than one sign-in method, such as the Authenticator app and a phone number.
• Use passwords that are long and unique, ideally stored in a password manager.
• Keep devices, browsers and apps updated.
• Train people to recognise fake sign-in pages, one of the most common ways passwords are stolen.

If login problems are taking up your team's time, our managed IT support team can sort them out and set up your Microsoft 365 so they happen less often. Get in touch for a chat.

Further reading

• Microsoft Learn: manage a user's authentication methods
• Microsoft Learn: how self-service password reset works
• Microsoft Learn: smart lockout