Render texture appearing as black in scene

I’m trying to have a sprite display what a camera sees. Right now I have a render texture showing what the camera see then a material showing what the render texture see applied to a sprite, but in the scene view and in-game the sprite only shows up as black. In the assets folder both the material and render texture show properly. What can I do to fix this?

Of course, this is not a perfect solution but by creating a cube then applying my material to the cube it worked fine, I then used that cube as the sprite needed.