I've been a using TeamViewer for a number of years. Most crecently, version 12 on a MacOS Sierra 10.12.5 will launch, but will not connect to any partners. Seems to have started after the upgrade to 12. I've uninstalled and reinstalled. It shows partners online, but won't connect to any of them, no matter what OS they are running. I've uninstalled and reinstalled as well. Any ideas?