Could not connect to partner - ipv6 fix does not work

As others have reported, I am getting the "Could not connect to partner" message when I try to connect and remotely control another PC on my LAN. Both PC's are running Windows 10, both are visible on the network (using Orbi router & satelite), and Teamviewer is running on both machines. The remote PC is setup for unattended access, but I cannot connect to it at all. I have tried the ipv6 fix, the network adaptors on both machines have ipv6 unchecked, but it had no effect. Both machines have been rebooted since the ipv6 change and I verified that the adaptors do have the ipv6 protocol unchecked. At this point, I am out of options, any suggestions on what to try are appreciated!!