I talked to Mathworks about this and their answer was: “yeah it doesn’t work in MATLAB2018. Download MATLAB2019!” It worked!
But man, it is so poorly managed. Why don’t they just add an error popup saying “Sorry! Live script is not supported in MATLAB2018 for your OS! Please download Matlab2019 and try again!” Such a simple solution. Wasted so much time of many people’s.
I don’t know if it will solve Everyone’s problem. Maybe some were using 2019 version and having the same problem? Idk. But if you are using 2018 and having the issue, try downloading 2019.