Access setting not working in Cron/Feed

The access level setting is not working when I use the Cron/Feed feature to create a feed. ]

The feed works if the setting = Public, but does not work if set to another user group (i.e. Super Users, Special).

If set to anything other than Public, the feed renders:

{"result":"error", "error":"ACCESS_DENIED"}

I have tried clearing cache and cookies but it still does not work.

I've attached a screen shot of the report setup.

vDAta v2.9.9
Joomla 3.6.5

If you set the Feed to a different access level then you must pass the authorized username and password as GET ( in URL ) or POST variables ( via CURL or Form submission etc ).