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Outlook and Microsoft 365 Sign-in Issues

A user can't sign in to Outlook, Teams, Word/Excel or the Microsoft 365 web portal, or is stuck in a sign-in loop.

Outlook desktop, Outlook on the web, Microsoft 365 apps on Windowsabout 4 min read

Symptoms

  • Outlook keeps asking for the password, or shows "Disconnected" / "Need password".
  • Office apps say "Sign in to activate" or "Unlicensed Product".
  • The sign-in page loops, or says the account doesn't exist or is blocked.
  • MFA codes or approval requests never arrive.
  • Error messages such as "Need admin approval" or "Something went wrong".

Before you start

  • Can the user sign in on the web? Open a private/incognito browser window and go to the Microsoft 365 portal (office.com). Web works but the desktop app doesn't = a local app/credential problem. Web fails too = an account, license, network or service problem.
  • Does this affect one user or many? Many users at once suggests a service issue. Check Service health in the Microsoft 365 admin center (admins only), or tell your lead.
  • Has the password, phone, or MFA method changed recently?

Steps

  1. Check the account first: is it locked, expired, or blocked from sign-in? (See Password Reset and Account Lockout.) In the admin center confirm the user has a license assigned.
  2. Check date, time and network. Wrong clock time can break sign-in. Make sure the PC has internet (see Wi-Fi Not Connecting) and isn't on a captive-portal network.
  3. Sign out of Office: in any Office app go to File > Office Account > Sign out, close all Office apps, then sign in again.
  4. Clear stored credentials (Windows): Control Panel > Credential Manager > Windows Credentials. Remove entries related to Office / Outlook / Microsoft (for example names beginning with MicrosoftOffice16, or containing outlook.office365.com). Restart Outlook and sign in again. Only remove Microsoft-related entries.
  5. Check "Access work or school": Settings > Accounts > Access work or school. Make sure the work account is listed and not showing an error. If the device has a stale entry, disconnecting and reconnecting may be required, but do this only if you know it's allowed for managed devices.
  6. MFA problems:
    • Check the phone has a connection and the authenticator app's notifications are allowed.
    • If the user has a new phone or the method is lost, an admin verifies identity then resets or re-registers the authentication method.
  7. Start Outlook in Safe Mode to rule out add-ins: press Win + R, type outlook.exe /safe, Enter. If it works, disable add-ins (File > Options > Add-ins).
  8. Create a new Outlook profile: Control Panel > Mail (Microsoft Outlook) > Show Profiles > Add. Choose the new profile as the default, open Outlook, and let it re-download the mailbox. (Cached local items will re-sync from the server; check nothing is stored only locally, like old .pst files, before removing the old profile.)
  9. Update and repair Office: File > Office Account > Update Options > Update Now. If still failing: Settings > Apps > Installed apps > Microsoft 365 > Modify > Quick Repair (then Online Repair if needed).
  10. Microsoft Support and Recovery Assistant (SaRA) is a free Microsoft diagnostic tool that can detect many Outlook/Microsoft 365 sign-in problems. Check that your organisation allows it before using it.
  11. Read the exact error and write it down. Searching Microsoft's documentation for the exact error code usually gives the next step.

Escalate when

  • "Need admin approval", conditional-access or "blocked by your organisation" messages (needs an admin).
  • The user has no license, or the license assignment is wrong.
  • Many users are affected (possible Microsoft service incident).
  • You think the account was compromised (unexpected MFA prompts, mail rules the user didn't make, sent mail they didn't write). That is a security incident.
  • A mailbox appears missing or corrupted.

Ticket note template

Issue: Cannot sign in to <Outlook desktop / Outlook web / Teams / Office apps>
Exact error message / code: 
Scope: one user / several | Started: | Recent changes (password, phone, device):
Web sign-in (private window): works / fails | License assigned: Y/N/unknown
Actions: signed out of Office | cleared Credential Manager entries | Safe Mode test | new profile | Quick/Online Repair
MFA status: working / needs reset (identity verified by <method>)
Result: Fixed / Not fixed
Next step / escalated to:

View as Markdown

How to use this

  1. Search first. Type what the user is describing, like printer offline or locked out. The search reads the whole text of every runbook, not only the titles.
  2. Narrow it down if you want to. The topic links under the search box (Windows, Network, Accounts and so on) trim the list. Click one again, or pick All, to go back.
  3. Open a runbook and read down the page. Symptoms tell you if you are in the right place. Before you start lists the quick questions. Then work through Steps in order, simplest first.
  4. Know when to stop. The shaded Escalate when box lists the signs that it is time to hand the ticket on. If any one of them matches, stop and escalate.
  5. Copy the ticket note. The last section has a note template. Press Copy, paste it into your ticketing system, and fill in the blanks.
Words you will see
Runbook
A written set of steps for one kind of problem, so you do not have to work it out from scratch each time.
First-line support
The first person a user talks to. Fixes the common problems and passes the rest on.
Escalate
Hand a ticket to someone with more access or experience, with notes so they do not have to start over.
Scope
How many people or devices are affected. One laptop and the whole office are very different problems.
Ticket note
A short written record of what was reported, what you tried and what happened.

Why I built this

I'm a computer science student in Toronto and I'm looking for junior IT support and help desk roles. When I started practising troubleshooting, I noticed I knew a lot of individual fixes but not a calm order to try them in, or when to stop and hand a problem on.

So I wrote these twelve runbooks to put that in order for myself, and I built this site so they are easy to search and read. They come from public vendor documentation and common help desk practice. They are not copied from a workplace and they are not real tickets.

They are still a work in progress. If a step looks wrong or something is missing, I would like to know.