See the following pages for known issues with your Cloud Endpoints API implementation:
ESP in GKE with Istio
When the ESP is deployed in GKE with Istio, configure Istio egress gateway to bypass the network traffic to the following hosts:
- metadata server: 169.254.169.254
- service control: servicecontrol.googleapis.com
- service management: servicemanagement.googleapis.com
- cloudtrace: cloudtrace.googleapis.com
- hosts specified by the field
x-google-jwk_uri
in the OpenAPI config
This issue doesn't apply to the ESPv2.