I am running in a VM that is using Windows 2012 R2 and Sharepoint 2013 installed.

When I create a Office add-in that is empty. Or when I use one that is pre-defined like the examples in here.

I am getting the same error:

APP ERROR Sorry, we can't load the app. Please make sure you have network and/or Internet connectivity. Click "Retry" once you're back online.

enter image description here

The localhost web is accessible without problem. The web application is using IIS Express. Should I configure something on VM or IE options ? Already updated the Office 2013 to use the SP1.

  • Are you trying to add App from Windows Store? Are you able to browse internet from your VM? Commented Feb 8, 2016 at 13:01
  • Could you provide more details on which approach you choose from the mentioned post?
    – Unnie
    Commented Feb 11, 2016 at 21:53
  • @ThirusangurajaVenkatesan No, Yes.
    – Tito
    Commented Feb 15, 2016 at 10:48

3 Answers 3


Not sure if you understand the architecture of these addins, but it might help you troubleshooting the issue.

An office add-in is in basic a web page that is hosted in a sort of Iframe in the office application. So when you run the sample it spins up a local iis to host the site en load in the office client. For developing you don't need internet access, but it looks like the client could not connect to the website in the background. Or the website in the background is not started properly.

To be more specific you need to configure somethings described in here, some of those configurations consists on:

  1. Make sure the security setting, Display mixed content, for the Internet zone is set to Prompt.
  2. Make sure Warn if Changing between Secure and not secure mode is selected in the Advanced tab of the Internet Options dialog box.
  3. When hosting the app use always the IIS, create a directory, instead of using the IIS Express and run it using SSL.
  • Agreed. This error will also display if the webserver returns a HTTP/500.
    – Boland
    Commented Feb 10, 2016 at 23:24
  • 1
    I complemented you answer, bullet 3 was my problem. I should use the IIS and create a directory, instead of using IIS Express. Once you accept the edit I will accept your answer. :)
    – Tito
    Commented Feb 15, 2016 at 10:48
  • Nr 2 was the problem for us.
    – Fox
    Commented May 30, 2016 at 4:40

For those working with the yeoman generated React add-in template, I had to click on OK for a warning dialog that was requesting me to install the development certificate to allow this add-in. Once I did that and hit retry on the add-in window my add-in loaded correctly. The first time I launched it I didn't notice this prompt cause I switched between apps.


Using yeoman React CLI:

Based on this issue, as of NPM 7.x you must manually run npm run dev-server.

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