This is the documentation for ConfiForms Server/Data Center appHowever, this might also work for ConfiForms cloud and in most cases it does. But please see this page to understand the differences between server and cloud versions of the ConfiForms app.
When you have an application link between JIRA and Confluence configured to use oAuth2 and would like to use this application link in ConfiForms to create issues or just to show the data from your JIRA inside Confluence you will see the error reported when you try to use this functionality for the first time.
You do not have an authorized access token for remote resource.
In ConfiForms view macros (when a view has JIRA fields) and in the built-in JIRA macro for Confluence an "authorize service" link is provided, helping you to authorize the access token and start to use this integration (Confluence and JIRA application link)
More about oAuth2 and Confluence/JIRA integration read in Atlassian website