Why can't the sim card of Samsung mobile phone a7000 be read?

The mobile phone card cannot be used for the following reasons:

1. Insufficient contact between the mobile phone card and the metal contact of the mobile phone;

2. The mobile phone card is damaged;

3. Is the location a signal blind area or there is no signal suddenly.

Tips: You can try to put your mobile phone card in other mobile phones for testing. If it still doesn't work, I suggest you take your mobile phone card to the business hall for testing.