What Should I Do If an RDS for SQL Server Database Problem Causes a Connection Failure?

Check whether any of the following problems occurred on the RDS for SQL Server instance.

1. The RDS DB instance is not properly connected.

   Solution: Check the connection. If you connect to the DB instance through a private network, the ECS and DB instance must be in the same VPC and the DB instance can be accessed only through the ECS. If you connect to the DB instance through a public network, the ECS and DB instance can be in different VPCs.

2. The maximum number of connections has been reached.

   Solution: Use RDS for SQL Server resource monitoring to check if the CPU usage and the number of connections are within the allowed ranges. If either of them has reached the maximum, reboot, disconnect, or upgrade the specifications of the RDS for SQL Server instance.

3. The DB instance is abnormal. For example, the DB instance fails to be rebooted, the system is faulty, or the instance or any table is locked.

   Solution: Reboot the RDS DB instance to see if the problem is resolved. If the problem persists, contact post-sales technical support.