Media Capture issue with B

i was fallowing Blackmagic Video I/O Quick Start documentation page, everything seem to be working until the last part where you press Play and hit the P button to send the video capture back to the blackmagic card. but i get error saying (Blueprint Runtime Error: "Accessed None trying to read property MediaCapture ". Blueprint: Main Function: Execute Ubergraph Main Graph: EventGraph Node: Capture Active Scene Viewport)

there is a screenshot in the attachment showing the steps i made. as far as i can see the media capture is working fine in the editor i can send back video feed to the card but in the blue print the media capture node as you can see in the picture is empty it cant detect the card’s node in the asset section.