Help with; Maps need lighting rebuilt

Hi, I’m just getting back into using UE4 after a little bit, but I keep getting this error after I’ve rebuilt the lighting (See attached image) I’ve fixed the lightmap density and every asset is mostly/all in the correct resolution and showing green and was wondering if anybody had any solutions to this as I’ve had a hard time finding any answers, if so, dumbing it down slightly would be appreciated as I don’t quite have a solid grasp of the terminology that would be used for functions in the engine.

Thank you