When refreshing cube using MicroStrategy Dataset connector, “Invalid authentication mode” message is received.

Symptoms: 

When trying to use Dataset Connector to refresh a cube, execution fails with an error: 
 

“Error in importing file. Check the file to import.
[Retrieving data from data connector failed. 
Error in importing files. Please check the file to import. 


Error type: Data Import Error. Fail to fetch data. 
Please check whether IServer machine can access the data source. 
Cannot login. Please check your credentials.<br>ErrorCode: 
ERR003<br>Message: Invalid authentication mode<br>TicketId: (…).” 

Action:  

Creating a new cube using the MSTR data connector, will use a certain Library URL under the API server dialog: that Library URL will also be stored as part of the definition of the cube created. So the cube may have been created in the MD using a different Library URL as part of their definition.  
 
The error itself implies that the Library URL stored in the cube definition has an invalid authentication mode – it might have been changed from e.g. Standard to OIDC/SAML – which is not supported for the dataset connector.  
 
Potential workaround: re-creating the cube.