Troubleshoot issues for Office 365 admins

Sometimes, things just aren't working. Here's some help for fixing administrative problems with Office 365.

If you need immediate help, contact support. to help resolve your technical issues.

Troubleshoot Office installation issues

Do you need to install Office apps for yourself, or are the Office apps not installing for you or your users? Get help for your users, or expand an option below to get help for admins.

When you first sign up for Office 365 for business and you try to install Office (or Project or Visio if you've also signed up for a plan that includes those applications) you might see a message that says you can't install Office because you don't have a license. This could happen because of a delay between your initial sign in and Office 365 for business setting up your environment. Try signing out of Office 365 and then signing back in.

It could also happen because you haven't assigned a license to yourself or your users. Do the following to check your licenses.

Check that you have a license

  1. If you're not already signed in, go to and sign in with your work or school account.

    Note: If you're unable to sign in with your work or school account, you may be signing in to the wrong Office 365 service, see Where to sign in to Office 365.

  2. From the browser header, go to Settings Settings: update your profile, install software and connect it to the cloud > My app settings > Office 365.

    Office 365 Settings pane
  3. On the My account page, select Subscriptions.

    Office 365 Subscriptions page

    You’ll see the services that you're licensed to use, such as the latest desktop version of Office, Project, Visio, SharePoint Online or OneDrive for Business, and Exchange Online. If you don't see The latest desktop version of Office in the list (or Project or Visio if you bought plans with those applications), see Assign licenses to users in Office 365 for business.

Not all Office 365 plans come with Office. If your organization has an Office 365 plan that doesn't include the latest desktop version of Office, as the admin, you can switch to a different Office 365 plan or subscription.

If you're not sure what plan you have, follow the steps in What Office 365 for business subscription do I have? For a comparison of plans, see the small business plans comparison or enterprise plans comparison.

When you install Office it's automatically linked to your Office 365 plan. This means if you recently switched plans you'll need to uninstall and then reinstall Office to associate it with your updated subscription. Use this easy fix tool and then follow the steps to reinstall Office.

  1. Click this easy fix button to uninstall Office.

    Easy fix download button indicating an automated fix is available
  2. For the remaining steps showing how to save and use the easy fix, follow the steps for your browser:

    Edge or Internet Explorer

    1. At the bottom of the browser window, select Open to open the O15CTRRemove.diagcab file.

      Select Open to open the O15CTRRemove.diagcab easy fix tool

      If the file doesn’t open automatically, choose Save > Open Folder, and then double-click the file (it should start with "O15CTRRemove") to run the easy fix tool.

    2. The Uninstall Microsoft Office wizard launches. Select Next and follow the prompts.

    3. When you see the Uninstallation successful screen, follow the prompt to restart your computer for the changes to take effect. Select Next.

    4. Restart your computer and then try installing Office again.


    1. In the lower-lower left corner select the o15CTRRemove file and from the drop down, select Show in folder.

      From the dropdown, select Show in folder

      Double-click the download, o15CTRRemove to run the easy fix tool.

    2. The Uninstall Microsoft Office wizard launches. Select Next and follow the prompts.

    3. When you see the Uninstallation successful screen, follow the prompt to restart your computer for the changes to take effect. Select Next.

    4. Restart your computer and then try installing Office again.


    1. Select Save File, and then OK.

      Save O15CTRRemove.diagcab file in Firefox

      In the upper-right browser window, select Show all downloads. In the Library, select Downloads > O15CTRRemove.diagcab, and then select the folder icon. Double-click the O15CTRRemove.diagcab.

    2. The Uninstall Microsoft Office wizard launches. Select Next and follow the prompts.

    3. When you see the Uninstallation successful screen, follow the prompt to restart your computer for the changes to take effect. Select Next.

    4. Restart your computer and then try installing Office again.

Install Office

To reinstall Office 365 or Office 2016, follow the steps in Download and install or reinstall Office on your PC or Mac.

To reinstall Office 2013, see Download and install or reinstall Office 2013 on a PC.

For a detailed troubleshooting instructions, and to help your users troubleshoot potential issues, see Troubleshoot installation issues.

Troubleshoot problems with email

Email not working? Can’t connect or not getting through? Expand an option below to find out how to diagnose and fix problems.

If you’re an Office 365 Midsize Business, Office 365 Business, or Office 365 Enterprise admin, you access and run the message trace tool through the Exchange admin center. To get there, do the following:

  1. Sign in to Office 365 with your work or school account.

  2. Select the app launcher icon in the upper-left and choose Admin.

    Can't find the app you're looking for? From the app launcher, select All apps to see an alphabetical list of the Office 365 apps available to you. From there, you can search for a specific app.

  3. Go to Exchange.

    Sceenshot of the Office 365 admin center with Exchange selected.
  4. Under mail flow, go to message trace.

If you’re an Office 365 Small Business admin, do the following to find message trace:

  1. Go to Admin > Service settings > Email, calendar, and contacts.

  2. Under Email troubleshooting, click Troubleshoot message delivery.

The mail flow troubleshooter is a simplified version of message trace that also checks for problems with your organization's domain settings. The tool can search for messages sent to or from your organization in the past week.

  1. Go to the mail flow troubleshooter.

  2. Sign in with a global admin account for your organization.

  3. Choose Next.

    Screenshot of the beginning of the mail flow troubleshooter with the Next button selected.
  4. Choose one of the symptoms from the list.

  5. Add the email addresses of the sender and recipient of the missing message. If you know part or all of the subject line, you can add that too, but it's not required.

  6. Select the date the message was sent.

    Screenshot of the input area of the mail flow troubleshooter. Admins are required to pick a symptom and add a sender and recipient email address before choosing Next to start the troubleshooter.
  7. Choose Next.

  8. The mail flow troubleshooter runs a series of tests and returns a result. If the troubleshooter found the missing message, the results page explains what happened and how you can fix the issue.

    Screenshot showing an example of the results of the mail flow troubleshooter.

If the mail flow troubleshooter wasn't able to find your missing message, use message trace for more powerful search options.

When Office 365 can't deliver email you sent, you'll receive an email notification called a non-delivery report. Find your error code for specific help with getting your email delivered:

Code 4.4.7

Code 5.7.12

Code 5.1.10

Code 5.7.124

Codes 5.1.1 through 5.1.20

Code 5.7.133

Code 5.4.1

Code 5.7.134

Codes 5.4.6 through 5.4.20

Codes 5.7.13 or 5.7.135

Code 5.6.11

Code 5.7.136

Code 5.7.1

Codes 451 5.7.500-699 (ASxxx)

For more troubleshooting information, see Troubleshoot email issues, My messages won't send and Fix Outlook account problems in Office 365 (English only).

Troubleshoot problems with Skype for Business Online

Problems with signing in or passwords for Lync? You’re not alone. Expand an option below to get help.

Most Lync sign-in issues can be traced to a small number of causes, and many of these are easy to correct. The table below lists some common causes of sign-in errors and some steps you or the users can take to resolve them.

Possible Cause


During sign-in, a dialog box appears that contains the following phrase: Lync cannot verify that the server is trusted for your sign-in address. Connect anyway?

Verify that the domain name in the dialog box is a trusted server in your organization—for example, Ask the user to select the Always trust this server check box, and then click Connect.

Enterprise customers can prevent this message from appearing when a user signs in for the first time by modifying the Windows registry on each user’s computer. For details, see Modify TrustModelData registry keys.

Mistyped sign-in address, user name, or password

  1. Confirm that the user’s sign-in name and password are correct.

  2. Verify that the user’s sign-in name is formatted as follows: This may be different from the format you use to sign in to your organization’s network.

Ask the user to try signing in to Lync again.

Forgotten password

Reset the user’s password and notify him or her of the new temporary password.

Not licensed to use Lync Online

Confirm that the user is registered as a Lync user. If not, register the user, and then ask him or her to sign in to Lync again.

Wrong version of Lync installed

This issue is usually associated with an error message that contains the following phrase: the authentication service may be incompatible with this version of the program.

Ask the user to uninstall and reinstall Lync from the Office 365 Portal.

Problem acquiring a personal certificate that is required to sign in

If the user’s sign address has recently changed, they may need to delete cached sign-in data. Ask users to sign out, click the Delete my sign-in info link on the sign-in screen, and then try again.

You set up a custom domain name, and the changes may not have finished propagating through the system.

First, ensure that you have modified the Domain Name Service (DNS) records to reflect the change. For details, see Update DNS Service (SRV) Records.

If you have already made the necessary DNS changes, advise the user to try logging in later. DNS changes can take up to 72 hours to be reflected throughout the system.

System clock out of sync with server clock

Ensure that your network domain controller is synchronizing with a reliable external time source. For details, see the Microsoft Knowledge Base article 816042, How to configure an authoritative time server in Windows Server.

Sometimes, the password box doesn't appear on the Skype for Business sign-in screen. If you’re signing in for the first time, the password box won't appear until you enter your sign-in address and click Sign in.

If you changed your password, the password box might not appear until you delete your old sign-in info . Here's how:

  1. In the Skype for Business main window, click the Options button The Options button in Skype for Business with the arrow on the right. and select File > Sign Out.

    A screenshot showing the Skype for Business options menu with Sign Out selected.

  2. Click Delete my sign-in info, select Yes, and then click Sign In.

    The Skype for Business sign-in screen, with callouts pointing to the buttons for Delete my sign-in info and Sign In.

  3. Under Password, enter your password, and click Sign In.

    The Skype for Business sign-in screen, with callouts pointing to the password field and the Sign In button.

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Still need help? Contact support.

As an admin for Office 365 for business, you get free access to our knowledgeable support agents for pre-sales, account, and billing support, as well as for help resolving technical issues. You can also contact support on behalf of Office 365 users in your organization.

Get help from the Office 365 community forums Admins: Sign in and create a service request Admins: Call Support

Note: If you’re using Office 365 operated by 21Vianet in China, please contact the 21Vianet support team.

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