Hi,
Today a customer call me and said that they cannot connect to meeting. In the Blog below is the fix.
https://blogs.technet.microsoft.com/uclobby/2017/05/24/lyncsfb-server-event-41026-ls-data-mcu-after-may-2017-net-framework-update/
And script that does this for You.
https://gallery.technet.microsoft.com/LyncSfB-Server-Disable-EKU-dab6cb88