With On prem resources, the resource group should be configured as your expressway. If you ae using the Default resource group, it will utilize the O365 connector, not the expressway / on prem resource, or the calendar connector.
Interesting, I have deployed this and didnt have to configure resource groups and I had no issues.
What is the status of the users on the connector host?
On the connector host, navigate to Applications > Hybrid Services > Calendar Service > Calendar Connector Status. If the users have been activated, you will see the number of users next to Successfully Subscribed Users.
Did you also configure the impersonation account in exchange?
You need to configure an. impersonation account and a throttling policy to use with the Cisco Webex Calendar Service. The impersonation account needs to be a mail-enabled account to use as the Service Account. The account does not have to be an administrator, but it must have a mailbox.
++ sample powershell script to configure impersonation and. create the mail box ++