skybox problem

I get this specific error every time I use a skybox that has HDR properties like sky_gravel_01 (the one I want to use) according to the sky list on the developer wiki. I don't get this error when I use a non HDR skybox like sky_badlands_01 (the one I've been using to avoid the error thus far)...

I downloaded this skybox (https://tf2maps.net/downloads/sky_starclear_01.17080/) from this website, and when I ran my map through a debugging program, it said it wasn't valid. Any help?

hey, this is my first post on this forum, and I'm making a tf2 map (shocking I know) and I've been having this problem that's plagued my map for months now, sometimes it stops and works other times it doesn't, I've tried taking the map apart and putting it back together and I just cant figure...

Hello! So I have a decompiled map that I want to make an edit for. I have a problem fixing the skybox of the map, the map's skybox doesn't show up like pictured below. I have followed along both 3kliksphilip's and TopHATTwaffle's tutorials and I added a sky_camera in the skybox and the...