After converting your SAP system to Unicode, on login you see the following messages:
 Process task Check Namespace is UP failed.
 Login with user account RFC_SIAM failed.
[System.Exception] Access to /VIAENET/ denied.
at StdioProcessor.StdioProcessor._Execute(Job job)
The string parts of transports are converted to Unicode, but the flag identifying the module as “non-unicode” is not changed. This results in a program abortion.
Load the Unicode transports.