A few things you might try:
- Make sure the Z position of the map is not the same as the others. Try setting it to -5.
- Make sure the Z position of the camera is not the same as the others. Try setting it to 5, or 10.
The three boxes are X, Y, and Z. The one on the right is the one we want to change. This can be found in the scene editor.
- Make sure the scene was loaded.
This has happened to me before, so you might want to check ;)
- If the background is being covered by other tiles even though they are transparent, make sure to put them in another layer.
This can be done in the tilemap editor.
- If the actors are covering the background, make sure the sprites are transparent.
You can check this in the sprite asset.
Other than that, I'm not sure what it might be without some more info. I hope this helps you find out what's going on. :o