Some of the settings such as deletion of key registration data can only be changed while the Bluetooth connection between smartphone and door is established. (Transmission Area)
When staying outside of Transmission Area, the items number 1⃣～6⃣ below will be greyed out and not available for use.
Please make sure that the smartphone's Bluetooth is turned ON while performing the setting change near the door. (Within 1m proximity from the door)