I don't know quite how or when I turned this on, but it turns out Bluehost has a very nice single configuration to sue Letsencrypt to get a free SSL certificate.
But if you have their Sitelock tool on, then SSL doesn't work and you can't access it. I have to say their chat is pretty good and I would have never figure this out with it!
The confusing thing is that Bluehost adds SiteLock Lite to all new accounts, so beware. And it will generate notices to you. Watch for various things injected into your .htaccess files by Let's Encrypt.
It looks like in my billing that this SiteLock lite was added. I didn't see it because I was using a subsidiary domain tongfamily.com and only just switched to using richtong.com.
As an aside, you can turn this off by turning off the CDN entry in WordPress at https://my.bluehost.com/hosting/wordpress_tools/performance