Azure APIM - Istio Ingress Gateway - AKS

We are using the Azure APIM to call Microservices, we installed ISTIO 14.4 in our AKS clusters, Using ingress gateway external ip we are trying to call microservice deployed in AKS, but we are getting 500 internal server error
These are the istio-proxy logs

2022-11-04T12:51:00.005Z] “- - -” 0 UF,URX - - “-” 0 0 0 - “-” “-” “-” “-” “xxx.xx.x.xx:0000” PassthroughCluster

Can anyone guide us in this regard