One of our users frustratingly pointed out that they could not start a IM conversation with someone.
The person who initiated the IM was from the full Lync 2013 client, and the person receiving the IM call had both the full Lync 2013 client and the Lync 2013 mobile client logged in.
After looking at the Diagnostic Report for the failed conversation, the reason for the failure was "The request was rejected because the application did not respond to the incoming call and it was not the preferred endpoint."
What does this mean and how can I prevent it from happening in the future?
Thanks
Ron