Custom Skybox Issues

Game Modding | Call of Duty: Black Ops 3 | Radiant

SGT.FUNNYMAN:

Hello guys so I've been working on adding 2 areas of the map, one on the moon and one not, I was wondering if multiple skyboxes was possible one for each area along with that I keep having issues with custom skyboxes not working, ending up as the default error color. Is there any way to fix this issue? I've tried numerous different images but all end up that way. Here are a few screenshots of the issues.

Any help would be greatly appreciated the final screenshot shows the two separate parts of the map, one with the main skybox and the other part without one,