istio logs a are not showing in Azure monitor.

[anishmarokeyGitHub]

I have followed below steps.
https://github.com/microsoft/aksworkshop/blob/master/_entries/02-06%20challenge3.md

When I Query , I am able to see data

InsightsMetrics | where Name == "jaeger_collector_spans_received_total" | where Namespace =="prometheus" | project Name, Val, Tags , Namespace, TimeGenerated , Computer

When I query(Istio), not able to see data.

InsightsMetrics | where Name contains "istio" | where Namespace =="prometheus" | project Name, Val, Tags , Namespace, TimeGenerated

Why my istio logs are not forwarding to Azure monitor