Problem with my level wad..

Hey, I seem to be asking a lot of questions, sorry!
anyway, I'm making my first level, I am almost finished, but I have one problem, for the ceiling, I made the texture just black, like a bottomless pit. but it does this in-game.

Help would be appreciated! This is my first map, And if you need me to link the wad, I can.

Make sure the flat is PIT, as opposed to ~PIT. If that isn't the problem, I don't know what to say.

Is this a custom texture? I mean, if you're making a custom black texture... don't. PIT exists for this purpose.

That being said, if it is custom, make sure it's stored as a Doom Flat, and not a Doom Texture. SRB2 is not ZDoom, so it cannot render normal textures on floors and ceilings, nor flats on walls; each must be on its respective designated area, and in the correct format at that.