3217998 - Cannot establish a Microsoft SQL Server via SAP Cloud Connector - SAP Data Intelligence

• You want to connect an on-premise MSSQL database from SAP DI Cloud through SAP CC
• MSSQL and SAP CC are installed on same host
• Back-end MSSQL system has been correctly configured in SAP CC, meaning the system is reachable: https://help.sap.com/docs/SAP_DATA_INTELLIGENCE/ca509b7635484070a655738be408da63/3cec4528a1d44efcb7be1adbf0f2286e.html
• SAP Business Technology Platform environment is able to connect to SAP CC
• SAP CC is routing connections to back-end
• However, below error is returned when testing the connection from DI Connection Management application:
  
  Status code from service response:400, Message: Failed to validate connection. 
  Code: 1103002
  Message: Open request could not be performed due to error: Socket closed. Invalid attribute in connection string: DriverUnicodeType

• SAP Data Intelligence (DI) Cloud 2221.20.25
• Microsoft SQL Server (MSSQL) 2016 Express Edition
• SAP Cloud Connector (CC) 2.14.1

KBA , CA-DI , Data Intelligence , CA-DI-CP-PE , Pipeline Engine , CA-DI-CP , Core Platform , CA-DI-CP-PE-SCH , Pipeline Engine - Scheduling , CA-DI-CP-SEC , Security Infrastructure , Problem