When you get this response envelope
{ "code" : "/api/status/error", "messages" : [ { "info" : { "count" : 2, "result" : [ ... ] }, "path" : "<key-string>"
it means that in your query somewhere there is a query node with a key equal to the path mentioned in the error.
... "<key-string>" : { ... }
The value of that key is { ... } when it should be [{ ... }]. So, add a pair of brackets to fix the error.