We had a similar error messages in 10.5.1 and was resolved by these resolutions, not sure if you have the same problem. Hope this helps.
Error "Unable to connect to the data source" When Opening a View after Change of Ownership | Tableau Software https://kb.tableau.com/articles/issue/error-unable-to-connect-to-the-data-source-when-opening-a-view-after-change-of-ownership
Thanks for your reply!!!
Unfortunately our problem is different
We tried Publish the workbook with "Embedded Password" and I'm the Administrator so granting permission won't help
Hmmm, here's some other things we did to troubleshoot (maybe you already tried this).
1) on the data source, click "Test Connection" button to see if it can connect
2) open a case and send Tableau the log file with error
Hope this helps
Maybe you had some solution for that problem because I also have the same problems, even tableau does not respond to the case, meanwhile I wanted to know if you have any solution?