I'm trying to add Jira gadgets to my Confluence pages. The experience I'm having is that sometimes it works, sometimes it doesn't. When it doesn't work I get this message:

Sometimes this message will be displayed in the configuration of the gadget so that I can't even set it up. Other times it will allow me to configure it just fine, and then when I view the page the gadget will sometimes load properly, and other times it will end up displaying this same message. At this point I can keep hitting F5 and sometimes it will load, sometimes it will not.
This is not a very good experience at all, of course. Any information on how I can get this resolved would be greatly appreciated. Thanks!