Is it possible to send a live video feed to server from Essential+?

From the question I am guessing this is not development question. I am guessing you are looking for Interconnect..

https://www.milestonesys.com/solutions/hardware-and-add-ons/milestone-addons/interconnect/

The answer is no. XProtect Essential+ is limited so that it cannot be used in interconnect.

https://www.milestonesys.com/solutions/hardware-and-add-ons/milestone-addons/interconnect/

Actually it was for development purpose. I saw anexample for video playing in SDK (MediaLiveViewer) but I wanted to know if live video from local VMS could be accessed by a central VMS.