No index available on keyspace in couchbase

I have a couchbase DB with documents stored, like

{
  "_host": {
    "kind": "KIND1",
    "id": "ID1",
..
}

I have created this index:

CREATE INDEX `kind-id-index` ON `dev`(`_host.kind`,`_host.id`)

but when I use this query

@Query("#{#n1ql.selectEntity} where _host.kind=$1 and _host.id=$2 ")

I got this error:

No index available on keyspace dev_wk_state that matches your query.

The back ticks are at wrong place. The index must be as follows.

CREATE INDEX `kind-id-index` ON `dev`(`_host`.`kind`,`_host`.`id`);

As there is no special characters in the fields you can omit back ticks also.

CREATE INDEX `kind-id-index` ON `dev`(_host.kind,_host.id);

FYI: _host is object and kind is field(nested) in object. You reference as _host.kind or `_host`.`kind`. If you do `_host.kind` it looking field "_host.kind" not sub object. If you want reference s1 you must use `f1.f2`.s1 because there is dot in the field you must do `f1.f2`.s1

{
  "_host": {
    "kind": "KIND1",
    "id": "ID1"
     },
  "f1.f2": { "s1": 10}
}