yWorks Diagrams for Confluence doesn't start! Why?

yFiles Flex powered applications, just like the yWorks Diagrams for Confluence plugin may not display or load properly in newer versions of some browsers.

This is due to a policy change that was implemented in user agents in 2017.

Luckily there is an easy fix or workaround that can be applied:

Pages or domains providing Flash content have to be marked explicitly as allowed to display Flash Content. This is browser dependent, of course.

For Chrome you'll find assistance here: https://support.google.com/chrome/answer/6258784?hl=en,

And for Safari here: https://helpx.adobe.com/flash-player/kb/enabling-flash-player-safari.html

For Firefox you'll need to click the icon on the far left of the adress bar that shows that a plugin on the page was disabled.