When Unity SDK renders images to a mesh, why can selecting "Universal Render Pipeline > Lit" render successfully, but selecting "Universal Render Pipeline > Unlit" cannot render?

• Unity 2018 version can render video images normally using the lightweight rendering pipeline. It is recommended to use Unity 2018 version first.
• After Unity is upgraded to version 2019, through testing, whether ZEGOCLOUD or competitors' Unity SDK, selecting Universal Render Pipeline > Unlit will result in the inability to render images.