Error inserting client com.mysql.jdbc.exceptions.jdbc4.CommunicationsException:

Hi good morning.
I have a desktop application, in Java, which shows the list of clients. And I can’t insert a new record in mysql server. from my PC, if it shows the data entered, therefore it means that the connection is correct.

The error it shows is:
The last packet successfully received from the server was 12.648 milliseconds ago.

Can you help me, please.