Error - Unable to determine event source based on event. - Apollo-Server-Lambda

I am getting this error whilst trying to use an Apollo Server with Lambda:

My site is https://unrivaled-licorice-5d985b.netlify.app/.netlify/functions/graphql

I have no idea what this error means so I was hoping someone could help.

Does anyone know of any fixes to this error, I have seen other people have the same issue but have been unable to solve the issue using any of their fixes

Please refer to: