Content was blocked because it was not signed by a valid security certificate when running Office Add-Ins

Hi All,

While i was developing an office add-in and using IE to view a deployed outlook add-in i was getting the following error:

Content was blocked because it was not signed by a valid security certificate.

It turns out that this issue is related to a self signed certificate that is being used on my local web server using gulp-webserver plugin; since i am using Visual Studio code in developing my office add-ins.

If you want to configure gulp server to use a certificate, open gulpfile.js in your project and add https to the configuration of gulp web server as explained here.

The other solution is to use chrome instead and not IE since IE requires self signed certificates to be added as a trusted certificate in your machine. So if you don't want to go through adding a self signed certificate to trusted certificates store, just use chrome and your add-in will load with no issues.

Hope this helps.