Identify an RDS connection failure caused by a client problem from the following aspects.
In Windows, check whether the RDS DB instance port is enabled in the Windows security policy. In Linux, run the iptables command to check whether the RDS DB instance port is enabled in firewall settings.
Check whether the connection address, port parameter configuration, and JDBC connection parameter configuration are correct.
Check whether the user name or password is correct if an error message similar to the following occurs during RDS DB connection:
If the problem persists, contact post-sales technical support.