Istio-sidecar-injector failing


Our implementation for istio on GCP which was working earlier is failing now. We are getting error message -“Does not have minimum availability” for istio-sidecar-injector.
Recently, we had tried to optimize the cost for Kubernetes cluster by scaling the nodes down to 0 multiple times and bringing them up. No other changes were done.
Also, since we had been getting the attached error message below, we had upgraded the cluster version to 1.23

Inspite of all this side injector is down and we are getting ‘No healthy upstream’ message while opening our application.