I’ve used the classic app to manage a couple of out of town Airbnb’s. In the classic app you could easily create lock codes and delete them. The classic app has become so buggy it’s close to unusable. Since it appears the classic app will not be supported soon I’m trying to make the new app do what I need it to. I added the smart lock guest access, which allows me to lock and unlock the doors. However, when I try to add a lock code, it tells me there are no online locks?
Did you check to see if you have multiple locations and if so, is the app and lock installed in the same location?
You may also want to check out LUM to create/manage users if you have access to RBoy Apps: [RELEASE] Lock User Management - Door lock code manager (create, delete and schedule codes) with automatic lock/unlock, custom user actions and SHM/ADT integration (LUM)