Since we are only hosting the phone number, we are subject to the authority of the voice carrier. If you are running into issues where you loose your SMS capabilities, it is most likely due to the voice owning carrier taking back the number. When we initially host the phone number we request provisioning from the voice carrier but unfortunately if they do provision back (be it intentional or incidentally) it can put the hosted SMS functionality down. Though it cannot be prevented, if you find yourself in a situation like this you can reach out to our team for resolution. Clerk is able to remedy/resolve and reach out to our carrier peers as needed to mitigate if this becomes a more regular occurrence.