How to fix a hole in the mesh I am watching Blender Guru's tutorial on how to make a donut and he is making a cup of coffee but for whatever reason whenever he does CTRL R to fix the hole in the middle of the liquid it works for him but I have tried it many times and it doesn't do anything. Please help me.
I don’t think there is a hole - it looks to be refraction showing the inside of the cup. Try reducing the IOR of your shader and see if the problem goes away - that will show whether there actually is a hole. Also, check your normals as that is critical with refractive surfaces since flipped normals will also flip the refraction properties. Also check that you have a realistic IOR for the material being modelled (eg, typically in the range 1.0 for air to around 1.33).