I have the same issue (running on mac).
How does the link help? It does not lead anywhere now.
The same article can now be found at https://support.wolfram.com/12464
Thanks! though I don't think this the issue (the Mathematica on my machine was just installed). I think there is a lag in Mathematica when typing on cmd+c, and therefore id does not copy. It happens to me on my desktop as well.