Had a tricky situation connecting Report Builder 3 to a cube. I was able to copy the connection string from withing SSDT but it still would not work.
I will use “Adventure Works” for illustration.
The solution was in the error message “Either the user, does not have access to the AdventureWorksDW2012 database, or the database does not exist.”
It turned out the database did not exist … as its SSMS Database-Engine name (“AdventureWorksDW2012”).
Connecting SSMS to Analysis Services however showed a different name “AdventureWorksDW2012Multidimensional-EE”
Plugging this into my connection string (with Data Source Type being Analysis services, and Connect Using being Windows Integrated Security) worked eg:-
Annoyingly (grrr!), I found just removing the Initial Catalog worked also (ah bah).