MongoCryptError: “not all keys requested were satisfied” exception. What this error mean?

We’re trying to use Mongo’s client side field level encryption, But I am getting "MongoCryptError: not all keys requested were satisfied. Verify that key vault DB/collection name was correctly specified.” on hitting the Query .

I am Unable to understand.
What this error mean? What keys?

Please let me help to debug the issue and solution for same.

Thanks in Advance.