Connect to public facing ip from internal host

I have configured Istio 1.0.6 to have Ingress to my HashiCorp Vault / IAM Solution and trying to configure OIDC. As part of this I need the Vault component to connect to the IAM Solution via its public FQDN so that it can get the correct config.

Browser -> Vault works
Vault -> IAM fails with

wget https://xxx.xxxx.xxx.com/openam/oauth2/.well-known/openid-configuration
Connecting to xxx.xxxx.xxx.com (172.20.xxx.xxx:443)
wget: error getting response: Connection reset by peer

I have tried to configure egress but it still fails.Is there a way to configure Istio so that internal hosts can connect to the Ingress gateway without using Mutual TLS?

Nicholas

upgrading to 1.2.4 resolved the issue.