Post Processing Effects not working despite correctly converting project to URP

Hi everyone, I am a student and for a Unity class we were tasked to work with the Post Processing effects in Unity. I wanted to take a project I had from last year because the lighting on it was atrocious and I wanted to improve it. I converted the project to the Universal Render Pipeline, I followed the guidelines on this exactly, and I configured it/updated my shaders to be URP. My scene looks different and the lighting was a lot better(and just easier to tweak to make it look better). I thought I had correctly changed my scene to URP. But when I go add a global volume and add overrides(I was testing it with a simple Vignette) nothing was happening and I am not sure why my post processing affects wont work. Yes, Post Processing is enabled on my main camera and yes the UniversalRenderPipelineAsset that I created is set inside of the Graphics -> Scriptable Render Pipeline Settings. Please help, I am extremely lost on what to do. Thanks!