We have the following onprem setup:
Exchange 2013(latest CU) + S4B(latest CU and the problem was also present when running Lync 2013)
A mix of Mac, PC and Mobile clients.
The conversation history works for Lync 2010, Lync 2013(ver. 15), S4B (ver. 16) and mobile clients of all flavors.
But the Lync for Mac client fails to save the conversation history on Exchange. When the setting is enabled to save it on the local computer it works as expected.
What could be wrong?
Answers to some questions:
The Lync for mac client supports conversation history in Exchange nowdays.
Test-CsExStorageNotification & connectivity command gives no errors.
Conversation history works when the same user logs on to a PC client.
Microsoft connectivity analyzer gives no errors regarding EWS for the user.