Thank you for your response Dawid. I removed the https (I had added it when I was trying to make stuff work) and I double-checked all the fields. No joy. I’ve given up on the React tutorial altogether. I assume I made some fatal mistake somewhere along the line and will have no way of figuring out what went wrong.
So, I created a new account with a new email and a new tenant and was able to get a plain javascript app up and running on that, which seems to behave correctly. I’m going to try to climb the learning curve from that.
Thanks again for the response.
Vineel