Jamming Project, this.props.onAdd is not a function

I am a bit confused on what happened while working on the Jamming project. I was working on step 63, I followed the tutorial and when I inserted the code for some reason the onAdd attribute became a typeError under the method addTrack(). This is weird to me because my code had been working all the way up to that point without saying it was a typeError. Would anyone have any idea why that would happen? I have looked over the code, went through the video and tried going through the console to figure out what went wrong. Would anyone have an idea? Thank you!