how can i do to background visible?

My background looks transparent. What can I do to make the sky visible like daz?

i can't find poser option to background visible..

and can anyone tell me change my hdr sky?

when i load only hdr sky light and rendering, it just look black. no sky.

I'd like to ask the producer, but there's no way to contact him.

i bought this:

https://www.daz3d.com/orestes-iray-hdri-skydomes--cassini