The cause is one of the followings. 

1

Inside lock button's response will become weaker if put closely to electronic devices such as smartphones and remote controls.
Please keep inside lock button apart from electronic devices before using.

 

2

Inside lock button might not respond during locking/unlocking operation or while establishing connection.

Please wait a moment before operating again.

 

3

For inside lock button, the connection will start establishing only after pressing button which makes operation via inside lock button somewhat slower than that of smartphone. Please keep in mind that this delay in operation is intended mechanism and not the malfunction.