Question about traefik metric traefik_service_requests_total

Hi folks!
we are using traefik:v2.5.2
We are also using the metric traefik_service_requests_total to return "client side error" of services. But dont know is correct.

sum(increase(traefik_service_requests_total{cluster_arn="$cluster",code=~"4\\d\\d",service=~"$service@ecs",job=~"$job",protocol=~"$protocol"}[$__interval]))

)