Hi @Kovács, Ferenc ,
Thanks for using Microsoft Q&A !!
I have tested this with 3 arguments and it works fine from Kusto Explorer.
Can you please share sql_request you are using along with the exact error message.
Note: For 3rd parameter (SqlParameters) you need to pass a constant value of type dynamic that holds key-value pairs to pass as parameters along with the query.
Thanks
Saurabh