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.%.
create user 'user_name'@'100.%' identified by 'password'; grant all privileges on *.* to 'user_name'@'100.%';
Error cause: The network between the DAS server and the GaussDB(for MySQL) DB instance is disconnected.
Solution: Contact technical support.