We had a report among some of our internal users of sign-in failures. Based on the log with numerous NTLM authentication failures that there is possibly an issue/bug with special characters in the password.
This user reported the use of (¥) which works on the Windows Lync client.
We also are hearing for Office365 and Lync for Mac issues which may or may not be related. If you are facing issues please open a support ticket for proper analysis towards a fix or documentation. If you have details of how you resolved or worked around the issue please share via comments and I’ll track back to support.