The indication means that the number of running applications have exceeded BLE(Bluetooth Low Energy) Limit which prevents My Entrance application from establishing a connection with the entrance door. 

Please follow the steps below.

 

①Please restart the device and open the application again.
The application should be able to connect with entrance door once the limit has ben reset.

 

②Please turn off other applications aside from My Entrance.
"Setting" → "Application and Notification" → Select application(s) → "Forced shutdown"

 

If the problem cannot be solved by above methods,

please contact customer support center or the store which you have purchased the product from.