The cause is one of the followings.

1

Remote control's response will become weaker if put closely to electronic devices such as smartphones.
Please keep remote control apart from electronic devices before using.

 

2

The remote control might not respond during locking/unlocking operation or while establishing connection.

Please wait a moment before operating again.

 

3

For remote control, Bluetooth pairing will only commence after pressing the button which makes operation via remote control somewhat slower than that of smartphone. Please keep in mind that this delay in operation is intended mechanism and not the malfunction.