At what point do you get the error and what database type are you connecting to? I know I've tried to connect to Materialized Views on Postgres in the past, and Tableau doesn't know how to read the metadata for these MV's. I created an idea to enable: https://community.tableau.com/ideas/8592
On the Data Source tab, after I drag the view to where it says "drag tables here", I receive the error. I am connecting to an Oracle db.
Based on this idea, Tableau appears to not know how to read synonyms, you should go upvote the idea. https://community.tableau.com/ideas/3515
If this is something different, can you attach a screenprint of the error?