I need to realize the preview of the attachment inside BPM process. I just add to the page, that implement human task, DocumentViewerTaskFlow. And added the resourceId for selected attachment as parameter for this taskflow. All is good, but the component only display the parameter of the attachment, and don't display preview. But I have configuring the Inbound Referiny - and all documents are automatically converted to the PDF. Also strange is that when I added DocumentNavigation component to the Spaces and select the same file - the preview is display success.
The problem was that it's necessary UCM connection type socket.