Hi Kashif Ahmed ,
Thankyou for using Microsoft Q&A platform and thanks for posting your query here.
As per my understanding, you are trying to read a Delta table and store it as a table in Azure SQL Database using Azure Data Factory Data Flow. However , the test connection is failing in sink settings while using the Linked service and dataset parameter. Please let me know if that is not the correct understanding.
While you are trying to test connection in the sink dataset, you might have been asked to provide value for the linkedserviceSecretBase. Kindly make sure you have provided the valid value there by manually trying to connect to the mySQL server using that value first.
Additionally, kindly make sure all the expressions used to parameterized the linked service and dataset ex: @dataset().LinkedServiceSecretBase etc are not copied and pasted, you have opened the add dynamic content option and selected the parameter which have generated that expression, else it would treat it as string, instead of passing the value by the system.
Hope it helps. Kindly let us know how it goes. Thankyou