If you are having issues signing out of Office 365 then follow the methods below to fix sign out issues.  You can also find the below information at the Microsoft Knowledge base. Office 365 signout issues

Method 1: Add sites to the “Local intranet” and “Trusted sites” zones in the web browser

  1. Click Start, type Control Panel, and then click Control Panel.
  2. Click Internet Options, and then click the Security tab. Note If Control Panel is set to Category view, click Network and Internet, and then click Internet Options.
  3. Add sites to the “Trusted sites” zone. To do this, follow these steps:
    1. Click Trusted sites, click Sites, and then click Advanced.
    2. In the Add this website to the zone box, for the following addresses, type each address, and then click Add:
      • https://*.microsoftonline.com
      • https://*.sharepoint.com
      • https://*.outlook.com
      • https://*.lync.com
    3. Click Close.
  4. Add sites to the “Local intranet” zone. To do this, follow these steps:
    1. On the Security tab, click Local intranet, click Sites, and then click Advanced.
    2. In the Add this website to the zone box, for the following addresses, type each address, and then click Add:
      • *.microsoftonline.com
      • *.sharepoint.com
      • *.outlook.com
      • *.lync.com
    3. Click Close, and then click OK two times.

Note: If you’re using single sign-on (SSO), your SSO addresses should also be added to the “Local intranet” and “Trusted sites” zones.

Method 2: Close and reopen all web browsers

Close all web browsers and then reopen them.

Method 3: Sign out of all Microsoft online services

You might be signed in to another Microsoft online service, and this may be preventing you from signing out. If this is the case, sign out of all Microsoft online services. To do this, follow these steps:

  1. Go to https://login.microsoftonline.com/logout.srf
          (https://login.microsoftonline.com/logout.srf)

    , and then sign out (if you aren’t already signed out).

  2. Go to https://login.live.com/logout.srf
          (https://login.live.com/logout.srf)

    , and then sign out (if you aren’t already signed out).

Method 4: Clear cookies from the web browser

Clear cookies from the web browser, and then try signing out again. The steps for doing this vary, depending on the browser that you’re using. For more information, see the following resources:

  • If you’re using Internet Explorer, see the following Microsoft Knowledge Base article:
    278835
          (http://support.microsoft.com/kb/278835/            )

    How to delete cookie files in Internet Explorer

  • If you’re using Safari, go to the following Apple websites:
  • If you’re using Google Chrome, go to the following Google website:
    Manage your cookies and site data
          (https://support.google.com/chrome/answer/95647?hl=en)

  • If you’re using Mozilla Firefox, go to the following Mozilla website:
    Delete cookies to remove the information websites have stored on your computer
          (http://support.mozilla.org/en-US/kb/delete-cookies-remove-info-websites-stored?redirectlocale=en-US&redirectslug=Deleting+cookies)