Not able to setup azure private endpoint url as webservice/backend for Azure API Management service

In view of APIM as the only public access point, with backend reachable only via private IP, would suggest:

1. Deploy APIM in Internal VNet Mode
•    Use the Developer, Premium, or Isolated SKU (Standard does not support full VNet integration for outbound traffic).
•    Enable VNet integration with internal mode so APIM can access private IPs.
•    Ensure APIM is in the same VNet or peered VNet as your Kubernetes load balancer.
2. Use Private DNS Zones
•    Ensure your private endpoint DNS resolves correctly inside the VNet.
•    Use Azure Private DNS Zones to map the private endpoint to a friendly FQDN.
3. Configure NSG and Firewall Rules
•    Allow traffic from APIM subnet to the backend IP and port (e.g., port 80).
•    Double-check that no NSG or firewall is blocking outbound traffic from APIM.
4. Avoid Using Public Endpoint in Backend URL
•    Use the private IP or private DNS name in your APIM backend configuration.
•    Do not use public FQDNs that resolve outside the VNet.