To integrate Exchange Online AA with Lync, we need to create a contact
Then get Identity, you can run run Get-CsExUmContact
but then if you try to call AA but sip, or number you will get an error (in Snooper).
SIP/2.0 500 Server Internal Error
CSeq: 1 INVITE
ms-diagnostics: 15014;reason="Hosted Voicemail Policy assigned to the user is not fully configured. Destination or Organization might be null";source="xxxx";appName="ExumRouting"
You will want to run another command to assign policy to this contact.
Grant-cshostedvoicemailpolicy –identity “paste-your-Identity as you see in get command above” –policyname O365
O365 is your policy as you defined in Exchange Online - refer to https://ahandyblog.wordpress.com/cloud-technologies/office-365-unified-messaging-with-lync-2013-on-premise/