Please make sure the Tableau Server machine has the driver installed and is allowed to access the database.
If that is not the issue, please make sure the Tableau Service Account has permissions to access the database or you are using a SQL login.
For more information about the Service Account, see the KB article: http://www.tableausoftware.com/support/knowledge-base/serverrunasuser
If you continue to have issues connecting, I do recommend contacting support. http://www.tableausoftware.com/support/request
did you find the problem ? i also have the same issue when publish views ....please help if you have fixed it .