I use TeamViewer. It works fine on Fedora 29 while logged into XORG, but on Fedora 30 I get the could not connect to partner error. I’ve replicated this three times on three fresh installs of Fedora 30. I just wiped my SSD again, reinstalled Fedora 29, and it works fine.
This problem extends to Plex. It will not allow any connections from outside networks. And again, it works fine on Fedora 29.