Microsoft launched a few days ago Skype for Business on Mac, which can be downloaded here: The purpose of this article is to provide the best practices on configuring your environment to get the best experience with this client, these recommendations were provided by Microsoft Beta team. It’s important to understand that, to have the best experience with Skype for Business on Mac, Microsoft recommends using Skype for Business Server 2015 with at least CU3 installed.
![Chat Chat](http://lyncinsider.com/wp-content/uploads/2016/11/skype4bmac_prefscalls.png)
However, if I delete all the old chats from the chat history/window, then double click on the contact again, a window shows up with the status light and display name: And in this window, I can send the message fine.
Regarding the configuration, make sure you have Server side Conversation History enabled and all the message history settings configured correctly.