I've been fighting with this for a week. I've finally got it to work. I re-paired the watch to the iPhone, as a new watch, rather than from a Backup. I'm not sure if this step was necessary, but it's what I did. In Device Hub, I have to click the add button, then choose nearby device. The developer mode option on the watch wouldn't appear until I did this. After enabling developer mode on the watch, I had to go back into the developer mode menu. At the bottom of that page, there is an option that says paired devices. After a couple of minutes, a button appeared there saying "Pair with MacBook Pro". When I tapped the button, pairing codes appeared on the watch, and in Device Hub. I confirmed the codes matched, and all of a sudden everything just started working. So, I'm not sure if that is just my experience, or the new way of pairing is initiating it from the watch end. Hope this might be of help to you.