After completing a Lync Server 2013 install I got some feedback that federation with Office 365/Lync Online users wasn’t working properly. On the other hand, federation with other Lync-enabled organisations was ok. Some of the symptoms, that I also verified using my own Lync Online account, were:
- On-premise users could see Lync Online users’ presence, and initiate IM
- Lync Online users could NOT see on-premise users’ presence, NOR could they initiate IM (message would time out with error message)
- Once IM was initiated from on-premise user to Online user, all modalities would work (although presence would take some time to update)
Rune's blog about things I see and UC 