I think I was impatient during the pairing process. The pairing code screen didn’t go away for a good minute after I had entered the code on my account page. So I deleted the device.
Now, however, I can’t get the Mark II to give me a new pairing code. I’ve rebooted multiple times. No joy. The Mark II lights up when I give it the wake word, but nothing I say is understood, or even logged on the Microphone page.