Wondering if anyone has successfully deployed ENSv2 on-prem? I've been going back and forth with Support for the past month trying to troubleshoot and get it set up but we've been unsuccessful. The EWS requests make it back to Exchange but a 401 status is returned.
We're running ENS v2 in the cloud, but had similar issues setting up. Are you using cert-based authentication? If so, make sure you have the EWS node in the default web site instance on your Exchange servers set to accept client certificates.
Not sure if it's the same setting, but also check in IIS Manager, Default Web Site, EWS. Select SSL Settings and make sure that Client certificates is set to Accept.