ODBC connection is very slow with MongoDB

Hi.

I am using an ODBC DNS to connect to the MongoDB BI connector to retrieve data from a collection (my collection has 5,000,000 entries) to PowerBI.

It works, but it is veeeery slow, and this is because it goes in 2 steps:

1) It displays "Waiting for dns=MyCustomMongoDNS" and stays like this almost 10mn

2) It actually loads the data (I can see the line counter increasing), and this step is going at an acceptable speed for an ODBC connection.

Does anyone know what is the ODBC driver doing at step 1 ???

Thanks!!