Printers are not being redirected via RAS Universal Printing Technology.
The following errors occurs in the Event Viewer on RDSH (Application and Service Logs > Microsoft > Windows > AppLocker > EXE and DLLs journal)
2xDevRedir.exe module is being blocked by Windows AppLocker. This is an RDSH add-in responsible for universal printer redirection.
Set up correct rules in Microsoft GPOs (both local and domain one) to allow the execution of the files located in RAS Installation directory (default C:\Program Files (x86)\Parallels\ApplicationServer)
For example, you may allow files execution from this location (default RAS installation directory): %PROGRAMFILES%\Parallels\ApplicationServer\*