Smart Lock Guest Access "No Locks Are Online. Try Again Later"

If they’re doing rentals, you may want to check out Rental Lock Automater, especially if they’re using AirBnB, VRBO or any similar booking provider. It completely automates the rental process and is much more reliable than Smart Lock Guest Access (e.g. it can handle temporary mesh and internet failures, it’ll notify them if something is wrong and automatically creates/deletes users).