Variables are not working

I want to use Grafana with elasticsearch exporter via Prometheus

and wneh i am creating dashboard for elasticsearch cluster
variables are not working

i have metrics in Grafana like this

elasticsearch_process_cpu_percent{instance="$instance",cluster="$cluster"

but no data, if i write without variables data are gathered

Could you please
to tell me maybe in elasticsearch exporter something wrong in settings but i have
all set
|es.all||

|es.cluster_settings||
What i am doing wrong?
Please answer me

can you provide more details about any specific plugins, datasources, and dashboards that you are using?