Queries not working? Think about this.
What makes a good story? Is it flowery description of a setting and character or is it meaningful conflict? The general answer is meaningful conflict where the stakes are high and the protagonist is changed by the end of the book.
So then, does your query concisely and compellingly describe the conflict and the stakes for the protagonist? Or does it briefly describe the genre, the characters, and story from 50,000 feet?
I've been reading a great compilation of advice on how to write queries here. There's a lot there and well worth reading. One of the KEY pieces of advice I've taken from it comes from an agent:
"I think the biggest mistake people make is not telling me what their book is about. They give an overview of the book in flowery writing that really doesn't say much, or they talk about the genre or the main characters etc., but they never tell me what the book is actually about and there's no way for me to judge whether or not I'm going to be interested in the story. Tell me who the main character is, what conflict s/he faces and what's at stake. You'd be surprised how many people don't do this."
And another agent:
"The bulk of a query should consist of 1) the main character, 2) what happens to complicate their life, 3) what goals they now have in response to that complication, and 4) the main obstacle between them and their goal. That is the cake of the query; everything else is just frosting and sprinkles."
One common mistake I think all writers make is they try to cram too much into an individual piece of writing because they want it to do too much. This is true of individual sentences, paragraphs, scenes, chapters, and books. It is also true of query letters.
A query's primary job is to get the agent or publisher to WANT to read your manuscript. You need a sentence or two to describe the business case for the book (your platform), but the primary objective is to create a sense of curiosity that you've written a good story. Your sentence or two on your credentials as a writer is how you entice them to believe you carried it off.
So, the reader needs to know what the conflict is and what the stakes are.
Remember: the query says I have a great story that is well told.