The documentation portal is undergoing maintenance. During this period, you can't create any new user credentials. If you do, you'll need to recreate the user credential after the maintenance period ends.
Effective in version 10.2 HotFix 2, Informatica dropped support for the DataDirect SQL Server Legacy ODBC Driver file
DWmsss27.x
because DataDirect no longer supports this driver.
When you use an ODBC connection to connect to Microsoft SQL Server, you can use the DataDirect 8.0 SQL Server Wire Protocol packaged with the Informatica installer, or any ODBC driver from a third-party vendor.