Hello!
We've been using Jira software for a while now and starting to explore Confluence (so still on the standard-free version) and I'm trying to see if this would be a good place to give an overview of a project.
I was having a play with the embed options, and came across Sprint Burndowns, but I either get nothing (very few options and a blank card) or an error.
Blank on published page:

Blank in edit page mode:

Blank in edit macro dialogue:

Error message in edit page mode (after re-inserting):

Having read through lots of documentation, I'm not sure if this is an add-on that I need to enable, or some other permission issue, as I can see other content from Jira (issue details, other charts etc.), or if this is a feature that's no longer supported (this article https://confluence.atlassian.com/doc/gadgets-204047542.html says support is ended, but then they don't appear in the macro browser, but sprint burndown does)