Thanks for the suggestion. I checked my laptop and discovered there was a different DNS configuration than on my iMac desktop. So I changed the laptop DNS so that it matches the iMac. Tried to connect with YouTube, and it still wouldn't go. I started looking around in the settings and found that I have a list of "preferred networks" -- my network at home plus lots of international hotels. I made certain it was selected to the correct network. Tried to connect with YouTube, and it still wouldn't go. I re-booted, thinking that would help. Nope, still won't connect to YouTube.
The problem with China censors is that they are tossing the baby out with the bathwater. I browse news sites regardless of where I am and, these days, most news sites are cycling video through YouTube, Twitter, whatever. I noticed while in Shanghai that I would look at a story on, say, CNN. The text would come up, but the accompanying video would just cycle and cycle and cycle. I glanced to the lower left and, invariably, it had hung up on one of the social media sites.
I wish I knew what mechanism they are using to block the sites. You never get a panel saying "The Site Is Blocked!" It just won't connect, or you will get "Trouble Loading Page".