I fixed my problem with this -- the clue was in the Email that Apple sent indicating there was a problem with the upload.
Turns out that when Xcode 8 automatically generates the Distribution profile, OR even if you had an existing Distribution profile that has an "entitlement" such as Push Notification set, your app MUST also have that set in its app.entitlements file. So while I am using Push Notifications, and it was set correctly in the Distro Profile, it was NOT "turned on" in the App/Target/Capabilities tab.
So once I turned it on in there, everything worked fine. My suggestion is to make sure that your self-generated OR Xcode generated Distribution Profile entitlements is matched exactly in your App/Target/Capabilities Tab.