Issue Summary

When trying to add a Sprint Health or Sprint Burndown Gadget in Confluence, an error may be encountered in the preview window.

Environment

Confluence 6.6.13
Jira 7.7.2

Steps to Reproduce

1. Register the external gadget
2. While editing a page, insert a macro and choose the Sprint Health or Sprint Burndown gadget

Expected Results

In the preview window, you will be prompted to authorize the connection.

Actual Results

You will instead receive the following error:
The resource /jira/rest/webResources/1.0/resources, cannot be found.
You will then be prompted for the authorization to Jira and the gadget will add.

Details

The trigger for this problem is the fact that gadget incorrectly fills form data for the POST request to: 

https://<confluence_url>/plugins/servlet/gadgets/makeRequest

In particular, url param is a relative URL, instead of being fully qualified (absolute) URL.

Workaround

Currently there is no known workaround for this behavior. This error will not stop you from adding the Macro, whether if you see the error in the UI or in a HAR file of the captured web traffic.