Viewport capture in runtime, black magic output not working!

[Frederic]

Blackmagic Video I/O Quick Start

So I am following this documentation to get an output SDI using the BlackMagic card.
Capturing the editor using a virtual camera works fine.
But when trying to capture the viewport in run time, it is not working.
I followed the exact steps mentioned in the documentation.
I am getting this error in the output Log :“LogMediaIOCore: Error: Can not start the capture. The Render Target size doesn’t match with the requested size. SceneViewport: 0,0 MediaOutput: 1920,1080”

[Noorenka]

You need to set it at the level blueprint. Check the resize source buffer, and set the custom capture point to 1920x1080.