The DB Instance Status in RDS describes the health of an RDS database instance. The status affects an instance’s ability to process requests and how you are billed for that instance. The full list of possible statuses is available here. A change in instance status may be user-initiated, caused by scheduled maintenance, or caused by a failure of the instance.
The severity of a Blue Matador event depends on the current status of an instance. Some statuses warrant an alert, some a warning, and others are just detected as anomalies.
If database access is not available, check with your team to see if any modifications were made to the instance size, config, or parameter groups. Reviewing the recent events for that database instance may tell you what led to the status change.