Your skybox is 1000 units wide, and you're setting the maximum fog range to 250. Therefore it stands to reason that anything beyond 250 units away from the camera will be totally fogged out/invisible.
The sykbox should always be parented to the camera, and reset the orientation of the skybox each refresh, i.e.:
The sykbox should always be parented to the camera, and reset the orientation of the skybox each refresh, i.e.:
RotateEntity SkyBox,0,0,0Just create the skybox, say, 5 units wide, and set it always be drawn first, using EntityOrder.