When I bind a camera with a device, why is a message "AZ-uuid-xxxxxxxxxxxx" indicating that the camera has been bound to another account and the device ID is invalid reported?

The device ID is used to prevent cross-region binding. A device can be bound to another account only after it is unbound from the previous account. If the previous account is in your family, submit a Technical ticket to Tuya and describe the situation. Tuya will unbind the device. You cannot perform the unbinding operation if the previous account does not belong to you.