Updated to the latest Office 2019 Pro Plus and it installed Skype for Business 2019 and stopped being able to see shared screens from presenters in meetings or when in single user meetings. The fix for me is listed below:
Run the following commands in a command prompt with elevated permissions'.
net stop winnat
netsh int ipv4 add excludedportrange tcp 50000 60
netsh int ipv4 add excludedportrange udp 50000 60
Reboot the machine
These commands create an exclusion for the port range these default ports are used by Skype when doing audio/video.