Virtual production composure SUSPENDED while in play mode

Hello everyone! I am currently working on virtual production project using UE4 with greenscreen for composure. I tried to make everything work in play mode, but the composure and its subcomponents are all SUSPENDED in play mode. I tried to make a BlackMagic Output and connected to a monitor but all the efforts were in vain. So are there any keys to this lock? Really appreciate it!

Are you playing back video in the composure? For some actions, you need to have a blueprint that keeps things moving or initializes properly.

No it is the livestream of a camera. Are there any details about the solution like what attribute should I use in the blueprint to make it come true?