onion skin appears black

I have Toon Boom (Harmony) Stage 10.3 and I was experimenting with the modules and the effects but when I got back to normal (removed any special effects from the network cuz I don’t need them), my onion skin turned black. I’ve searched on the Internet how to fix it but it didn’t work: I’ve tried to go to preferences and check if the colors are red and green/blue and they are. I can not find or tell where the problem is. Now it’s very difficult for me to animate with the onion skin that appears black just like the frame that I am on.
Basically, I must have pressed something that turned my onion skin black and not red an a bit transparent like before. I’ve attached a screenshot. Please help !! :frowning: