Hi all. Hopefully someone can shed some light on an issue we're running into. When calling the UM Subscriber Access number i connect to UM and get a prompt for my mailbox, after pressing in the mailbox number I'm met with "Your mailbox is not supported by this Unified Messaging server." This happens to every mailbox even newly created users. All users are supplied with Microsoft E4 licenses. Not sure why this is occurring. Other than that issue, on-prem Lync and O365 are integrated. Hosted Voicemail Policy is created and users set to Hosted VM True.
On a call with Microsoft support. Hopefully its just something on their end.