The Error Log - Medium Severity Error Log Message alarm becomes active when Spotlight Enterprise detects a new error message that contains one of the custom log entries of medium severity that are defined in the Error log entries configuration window.
When this alarm is raised view the SQL Server error log around the alarm time. (Amazon RDS for SQL Server | Error Log drilldown)
Note: Use the Spotlight Client Configure | Error Log Entries to define and edit the alert rules that Spotlight scans the SQL Server Error Log for. Spotlight scans the error logs at the configured frequency. If you make changes to the alert rules it may take some time for changes to take effect.