Based on discussions with the IBM Connections Level 3 Support Team, the Cloud install of IBM Connections does not support the "allow-forms" parameter of iframe HTML syntax in rich text fields. The application "strips" those parameters from the HTML when the rich text content is saved.
As a result, wikis that leverage embedded widgets from applications (such as BOX@IBM and others) that require authentication are not able to properly authenticate because the Form Submit action which permits the SSO Authentication page to be invoked is removed from the iframe HTML.
On-prem installations of Connections such as the IBM intranet installation on w3 work properly.
Therefore I would like to see the IBM Cloud Connections Environment / Wiki needs to allow Form Submit actions.