Do the users trying to connect to SSAS using Tableau Reader have access to SSAS?
Yes they have access to SSAS
When you say that the users have access to SSAS, are they able to access it using a desktop tool like Excel?
Recently when we had a similar issue, I have had to review the SQL Agent, Browser and network configurations on the SQL Server services to get this working.
can we use tableau reader to open a twbx based on SSAS cube ?
i don't think so !