Description* UPDATE: March 29, 10:22am
The certificate errors present on all servers have been resolved. This was a result of the previous change that was made yesterday morning and created some additional alerts in Lync that prevented server-to-server communication on the Front-End pool. To resolve this we needed to remove and re-assign the Front-End pool certificates to the Lync services and completely restart the servers. At this time confirmed all event viewer errors are no longer appearing and validated that I can see the presence of all users spread across each Front-End server. We will re-assess the situation on Monday to ensure services are fully operational and will send out any further updates if required.
After the recent update and restart of the Lync services, there are some certificate alerts present on the Front End servers that is causing some issues where you are not able to see the presence of some users (stuck at Updating...), and therefore not able to communicate with them.
We have opened an urgent case with Microsoft and will provide an update on this issue once we have spoken to them.
Sorry for the inconvenience!