Did you spell the name of the skybox correctly in Map Properties?
yes i copy and paste it
If it's a custom skybox, do you have the skybox files in your tf/materials/skybox folder? Is your map sealed, and did you use skybox brushes?
yes i used skybox brushes as always but i used the jungle skybox from borneo if that helps
According to the VDC, "This skybox will only work if you have the skybox files." I dunno if it's available to download somewhere but I can't find it on this site.
Separate names with a comma.