He is using an old 741 opamp. I pointed out that it will not work with its input voltages so close to its negative supply voltage that is 0V. It needs an additional negative supply.
Or he can use an opamp that has inputs that work all the way down to its negative supply (0V in his circuit) like an LM324, LM358, a few other older opamps or a modern rail-to-rail opamp.