There are a number of reasons why the add-in may be misbehaving in your environment. Please read through the following known issues to see if any help to fix your problem. If you are still experiencing issues after reading this article, click the How can we help link at the bottom of the page to send us a support request.
When launching the SharePoint Trial Web Location nothing happens. It just stays on the loading screen forever.
This is a known issue with Windows 10. Windows 10 has a bug that causes dialogs to be created behind other windows – instead of in front of them. The SharePoint Trial web location requires you to login and this login dialog is not displaying in front of Word.
Look in the Windows taskbar. You may see an orange flashing icon or an Internet Explorer icon at the end of the taskbar icons. Click it. This will bring up the login form for the SharePoint Trial web location.
The add-in does not look right or is not working properly
This may be caused by Corporate IT policies in Internet Explorer.
Please instruct your IT department to add the following URL’s to the Internet Explorer Trusted Sites list:
After clicking on my SharePoint Online (Office 365) web location, I am presented with a screen that says ‘This content cannot be displayed in a frame’
Sometimes the Office 365 credentials that you use can become mixed up if you are using multiple Office 365 usernames.
Reset your cookies in Internet Explorer.
- Select Tools > Internet Options.
- Click on the General tab and then the Delete… button.
- Make sure to uncheck Preserve Favorites website data and check both Temporary Internet Files and Cookies then click Delete.
source: https://kb.wisc.edu/page.php?id=12314. Retrieved on 2018-04-10.