Unable to retrieve doc present in Hidden Index for Alerting in Dev tools

Hi Team,

I checked with search queries to retrieve docs present in the hidden index for OD alerting index.
But it is not showing any doc.I have created 2 monitors including 3 triggers and alerts are getting generated as per triggers.

I used these queries to retrieve data from the hidden indexes.

GET _cat/indices?expand_wildcards=open,hidden

GET .opendistro-alerting-alerts/_search

GET .opendistro-alerting-alerts/_search

GET .opendistro-alerting-alert-history-2021.07.18-1/_search/

GET .opendistro-alerting-config/_search

GET .opendistro-alerting-alert-history-write/_search

GET _opendistro/_alerting/stats/

GET _opendistro/_alerting/monitors/stats
GET .opendistro-alerting-config

Able to retrieve the docs present in system hidden indices after making changes in elasticsearch.yml file by making opendistro_seccurity.system_indices.enabled: false