The shield icon that is being mentioned was not in the sidebar for me either, however I solved it doing the following:
Find the shield icon located in the far right of the URL input bar,
Once clicked, the following popup should appear wherein you can click Load unsafe scripts,
That should result in a page refresh and the scripts should start working. What used to be an error,
is now merely a warning,
OS: Windows 10
Chrome Version: 76.0.3809.132 (Official Build) (64-bit)
Edit #1
On version 66.0.3359.117, the shield icon is still available:
Notice how the popup design has changed, so this is Chrome on version 66.0.3359.117.
Note: The shield icon will only appear when you try to load insecure content (content from http
) while on https
.