Hi Anna
Thank you for your email. I changed the timezone on my macbook from UTC +10:00 Canberra, Melbourne, Sydney to UTC +4:00 Moscow. Then tried to sign into Lync again.
This was successful.
But caused issues with my calendar and email etc.
So I signed out of Lync, and closed the App. then changed the Timezone back to UTC +10:00 Canberra, Melbourne, Sydney. I then rebooted the Macbook. I was still able to sign in.
Is this what you were expecting to happen?
Thanks,
Nat