Dataflows error

Hello Everyone,

I am using Dataflows to connect through my client server and then pulling the data into Power BI using Power BI Dataflow connector. But whenever I applied any operations like count records, sum of a column etc in the edit query, this pop up comes that your access is forbidden.This comes even when I tried to merge two tables. Basically, I am getting the resultant tables, but can't test the records, matching records, duplicates etc because of this. Everytime I tried to check these, I get this access pop up.

What to do now ?

I am a Power BI Pro user and want to avoid fetching data via vpn and ssh tunnel. Therefore, used the feature of dataflows. Can Anyone please help me with this ?