It works in VB.NET but not in C#

I am idiot! And/or you have younger eyes than I!
Yes, that is it. They are both working now.
Can I just ask, because it was a long road to this perhaps simple, obvious code - why was it so hard to find this? I was trying code with client id’s and secrets and none of it was needed and didn’t work. This person’s VB.NET code was the only comprehensive example that I could run successfully.