Possible things to consider:
Amazon RDS for SQL Server address
The Amazon RDS for SQL Server address is entered on the Amazon RDS for SQL Server | Connection Details screen. In the Spotlight Client, click Configure | Connections and select the Amazon RDS for SQL Server connection type; right click on the connection and select Properties.
Check the address is a valid server name, server instance name or IP address.
Authentication
Authentication to the Amazon RDS for SQL Server is defined on the Amazon RDS for SQL Server | Connection Details screen. In the Spotlight Client, click Configure | Connections and select the Amazon RDS for SQL Server connection type; right click on the connection and select Properties.
The connection will fail if the account permissions are insufficient to allow Spotlight to collect the data it needs.
When Use AWS Managed Microsoft AD is selected then the account running the Spotlight Diagnostic Server is used to connect to the Amazon RDS for SQL Server.
When filling in the User and Password fields, ensure the database user has sufficient account permissions to retrieve performance data from the Amazon RDS for SQL Server instance. Typically the account will be a member of the processadmin server role. It could be a SQL Server login (such as ‘sa’). Alternatively an account can be configured with the necessary privileges as documented in the online help.
For additional information on script to grant permissions to TrustedUser, see Grant account permissions
Connection
The connection to the Amazon RDS for SQL Server host is defined on the Amazon RDS for SQL Server | Connection Details screen. In the Spotlight Client, click Configure | Connections and select the Amazon RDS for SQL Server connection type; right click on the connection and select Properties.
Microsoft Data Access Components (MDAC)
You may need to upgrade Microsoft Data Access Components (MDAC) on the Spotlight Client host AND the Spotlight Diagnostic Server host. More information is available from the Microsoft Download Center (search for MDAC).
Amazon RDS for SQL Server availability
Verify the Amazon RDS for SQL Server instance is available and accessible over the network.
Configuration
If this alarm is raised too often or not enough for a given Amazon RDS for SQL Server Instance you can configure certain parameters. See Configure Connections.