AWS DMS endpoint test connection error I am trying to migrate Microsoft SQL Server databases from on-premise to an RDS instance. I have created a SQL Server 2014 Express Edition instance in RDS and I have SQL Server 2014 Express Edition on premise in in my corporate network. I am able to connect to the RDS instance from my on premise SSMS. While using the DMS service to migrate and creating endpoints, I am getting below error. 


  Error Details:
  [errType=ERROR_RESPONSE, status=1022506, errMessage=Failed to connect Network error has occurred, errDetails= RetCode: SQL_ERROR SqlState: HYT00 NativeError: 0 Message: [unixODBC][Microsoft][ODBC Driver 13 for SQL Server]Login timeout expired ODBC general error.]]


I am getting the same error even when I am testing the target endpoint which is an RDS instance. I have kept RDS and replication instance on the same VPC. Port 1433 is open in my system and as I am able to connect to the RDS instance via SSMS so there shouldn't be a port issue.

Please help.
I had a similar issue, though I was using DMS to migrate data from S3 to an (RDS) SQL Server 2008. I figured out what my issue was, I didn't require SSL on the SQL Server endpoint. I additionally had to make sure my IAM policy had the right level of access to the services. Hope this helps.

Additionaly:


  AWS DMS currently does not support SQL Server Express as a source or target.


Reference: Troubleshooting Migration Tasks in AWS Database Migration Service (AWS Database Migration Service | User Guide)