It means that the lock is already connected to another property room, so you need to follow these steps:
If you have access to that property, log in and disconnect it via the Space app, or ask Goki support to remove it
Take the disc out (in the case of the SmartLock, if you have a SmartLock Pro skip this step)
Put the disc back (in the case of the SmartLock, if you have a SmartLock Pro skip this step)
Make sure it is placed/connected correctly
Reset the Smart Lock (press and hold the button on the back of the lock)
Close the app
Turn off the Bluetooth
Turn the Bluetooth on, open the app and try again