# GaussDB(for MySQL)

1. Error message: Access denied for user 'user_name'@'100.xxx.xx.xx' (using password: YES).
   1. Error cause: The username or password of the GaussDB(for MySQL) DB instance is incorrect.
      Solution: Check whether the username and password are correct. If you are not sure, log in to the GaussDB(for MySQL) console to view the username and reset the password.
      Changing the password may affect services.

      If the username and password are correct, log in to the database using a client or CLI tool and run select * from mysql.user where user = 'user_name' to view the account. Make sure that the DAS CIDR block is within the CIDR block of the user. user_name @ % and user_name @100.% are two different users whose passwords and permissions are independent. Make sure to enter the password of user user_name @100.%.

   2. Error cause: The IP address of the DAS server is not in the whitelist of the login user.
      Solution: Log in to the database using the client or CLI tool, and create a user that can be used to access the database through DAS.

          create user 'user_name'@'100.%' identified by 'password';
          grant all privileges on *.* to 'user_name'@'100.%';

      1. The IP address of the DAS server is in the 100.xxx.xx.xx network segment. Add the IP address to the whitelist of the login user.
      2. Grant permissions to user user_name@100.% based on service requirements.
2. Error message: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

   Error cause: The network between the DAS server and the GaussDB(for MySQL) DB instance is disconnected.

   Solution: Contact technical support.

Parent topic: Connection Management (Development Tool)