The cause is one of the followings. 

1

Key card/tag key might be swiped at the wrong area of the digital lock.
Please swipe the keys at the area with signal wave mark.（）

2

Key card/tag key might not be registered.
Please gather every key card/tag key and register them again.
How to register

3

The registration data of the current key card/tag key might have been deleted when other key card/tag key was re-registered. 
Moreover, the registration data might have been deleted by someone else using the application. 
Please check if other family members have deleted the registration and register the device again.

Please gather every card key/tag key when registering.

How to register

※For application version：V1.2.1, Door control program version：V2.1 and later, 「Individual registration」 setting makes it possible to register a new key card/tag key without losing former registration data which makes it unnecessary to gather every key card/tag key for each new registration. 
How to set up 「Individual registration」

4

When swiping, the door might not respond when the key card/tag key is put together with other contactless smart card (IC card) or small coins. Please separate the key card/tag key from other contactless smart card (IC card) and coins when using.