Can't access my business email in Outlook.

Test the mailbox in Outlook on the web first; if web access works, repair the Outlook desktop profile, but if web access also fails, have your Microsoft 365 administrator check Exchange Online service health and the account.

1. Isolate the problem

1. Open Outlook on the web in a browser and sign in with the same business account.
2. Also try another Microsoft 365 application, such as Teams or Word, if available.
3. Ask one colleague whether Outlook is working for them.

Use the result:

• Web email works, but Outlook desktop times out: continue with the profile repair below.
• Web email and other Microsoft 365 apps fail: contact your organization’s Microsoft 365 administrator to check your account, licence, and sign-in status.
• Several users are affected: an administrator should open Microsoft 365 admin center → Health → Service health → Exchange Online and review active incidents or advisories. Service health requires an appropriate administrator role.^1^

2. Repair the Outlook desktop profile

For classic Outlook on Windows:

1. Open Outlook.
2. Select File → Account Settings → Account Settings.
3. On the Email tab, select the business account.
4. Select Repair.
5. Complete the wizard, restart Outlook, and wait for it to reconnect.^2^

The Repair option is unavailable for Outlook 2016 connected to an Exchange account. If it is missing, proceed to the next section.

3. If repair does not restore the connection

• Run Windows Update, including available Microsoft 365/Office updates. Outdated software and damaged Outlook profiles are common causes of Outlook connection failures.^3^
• Run Microsoft’s Support and Recovery Assistant for Microsoft 365 and select the Outlook connectivity problem. The same Microsoft troubleshooting guidance provides this tool for automated diagnosis.^3^
• If the diagnostic cannot resolve it, provide your administrator or support team with:
  • The exact error text and any error code
  • Whether Outlook on the web works
  • Whether colleagues are affected
  • The approximate time the failure began
  • Whether the same account works in another Microsoft 365 app

Do not manually change IMAP/SMTP ports or registry settings unless your administrator confirms that the account is configured as IMAP/POP and identifies the applicable documented issue. A Microsoft 365 business mailbox normally requires troubleshooting appropriate to its actual account type.

References

1. How to check Microsoft 365 service health
2. Fix your Outlook email connection by repairing your profile | Microsoft Support
3. Fix Outlook connection problems for Microsoft 365 account