u/ImmediateJellyfish33

I am trying to install a bidet hose in my bathroom to a new Y shaped valve/connecter. When I screw it on it leaks (as shown in picture), and I don’t understand why. I thought it was a washer issue, there is a small grey washer wedged inside the middle hole, not seated as it’s too big. Is this the issue? Does a washer even need to be in that middle part? Aside from that there are two black washers on top of each other in the main part. is anyone able to tell me why it’s leaking and how to fix this? Thank you