Everything I have tried do not seem to get at the problem
Have you had the mobile unlock working before?
Any changes since then, ie new phone? If you do have a new phone, even though it has the same phone number, you have to set up the Passwordless Unlock again for that new phone. This is because Password Manager does not use your phone number to contact the phone, but the unique identifier for the specific installation of Norton Password Manager app on that device.