This continues to be a major issue for me as well Polestar01. Hopefully there’s some better answers than I am going to suggest.
The way I worked round this was to set up the SSAS server as a Linked Server on a on-prem SQL Server instance. Then you can connect (from KNIME) to a database on the same server as the Linked Server using a normal KNIME Microsoft SQL Connector node and use SELECT * FROM openquery(’[LinkedServer]’, ‘MDX/DAX as appropriate’) to query your cube or tabular model.
If you need more help, let me know.