Hi @rajanisqldev-42 ,
Thankyou for using Microsoft Q&A platform and thanks for posting your query.
For better clarification, could you please confirm if the parameter you created in the dataflow is of date datatype or string datatype. I would recommend you to keep the parameter as string datatype and use toDate() function within dataflow to convert it to date datatype further. Also, while passing the variable to dataflow inside dataflow parameter tab, check the expression checkbox.
Please let us know if it helps. Thankyou