The SQL for Confluence 11.x app version has removed the support for application server-defined data sources in Confluence 8.x. SQL for Confluence 11.x version works seamlessly with Confluence 7.x (Confluence 7.4 to Confluence 7.20) versions, including support for Application server-defined data sources (JNDI data source connections).
In Confluence 8.x, we recommend reconfiguring the application server-defined data source profile to the connection string profile. For more information, refer to How to convert an application server defined data source profile to a connection string profile.