In most cases you should not need to configure an allow list for the GTP Services. However, if your you’re having issues with connectivity to some GTP services Services you should add the following IPs to your firewall allow list. We’ve included IPs for GTP Services as well as those used for our service providers: Microsoft Azure and Auth0. In all cases we use a minimum of TLS 1.2 and port 443.
...
Our Auth0 domain does not support a static IP at this time. If you your firewall has the ability to allow by host name use gtpservices.auth0.com.
...
When you are receiving a response from our services the following ip IP addresses can be used:
GTP Services
...