CMS Guests Unable to Create Article
 

In one particular section I would like guests to be able to create articles. I have the permissions set in the AdminCP> CMS Permissions to ? Can Create, Can Read, Can Publish for Guests in that particular section.

I've gone into vbCMS and set the permissions "Can Post'.

and I've gone into the Unregistered/Guest Usergroup and set the permissions "can read, can post".

Cleared the CMS Cache and still receive a "You must register to access this page" warning. So what am I missing to enable Guest Posting in 1 (sub)section only.

Section is located:

Home> idea> contain > New Section