We use the Insert JIRA Issue/Filter widget on a lot of Confluence documentation pages but recently discovered that was failing to load the issues for users who are not logged into Confluence [the Confluence pages and Jira tickets] are public and are intended to be viewable by non-authenticated users.
The tickets can be viewed in Jira when not logged in [tested by checking the View in Jira button on the widget] but when viewing the Confluence page the widget just spin.
This worked correctly at one point.