Lighting build stuck at 0% and bug totally now

Hi i’m new to this and it’s been 3 weeks i’m training and building a project but i’m very close to give up everything because of a problem i can’t fix…

Since 2 days for no reason my lighting build is stuck at 0% for ever… even when i delete everything on the map and i simply put a blank box it’s taking for ever. I tried to start a new map and started to put some things on it and now, everything is weird, all build in 1second, when i put a light somewhere i have shadows, and when i build light it take not even a second and shadow deseaper…

I don’t understand, everything is broken what happen ?