Hi Bernard,
are you using the latest patch version of the .NET Connector 3.0? It should actually not matter, but it's always a good idea to use the latest NCo patch level. How do you pass the SSO ticket to NCo? Did you implement your own variant of an IDestinationConfiguration? Or do you create custom destinations and set the SSO property? What do the backend logs tell you?
Best regards,
Markus