Ultra task cloud url domain not working "demo-fm.snaplogic.io"

After replacing local IP and port number of the Ultra task cloud URL (No Authentication) with “demo-fm.snaplogic.io”, the HTTP post request is not working via browser or through Rest API Postman. The below is the error i get everytime.

Our team is also facing same issue while doing Ultra task. In postman, it is showing 404, but in task logs it is showing “plex and are in different organisations”.

(we are supposed to use “Cloud” account and creating task in that account, but in the certification demo videos & tasks documentation they mentioned to replace the IP address and port number with the URL: “http://demo-fm.snaplogic.io” which is related to Cloud-dev account).
We have already sent a mail requesting this issue but no response and our exam date is expiring soon. Awaiting your reply.