I have a similar situation. In the last couple of days, suddenly TeamViewer has simply stopped functioning and gives me a "Not Ready....".
I've uninstalled and reinstalled a few times; no luck.
I've uninstalled and gone through the registry and deleted all instances of TeamViewer; no luck.
Rebooted several times during the previous statements; didn't help at all.
Checked proxy setting in Internet Options; no luck.
All Firewalls disabled; no luck.
I can do everything else with regard to network/internet, just no luck with TeamViewer.
This machine HAS had the "Suspected Commercial Use" and "Detected Commercial Use" screens come up, though I don't know if that's part of the issue or not. It could be that TeamViewer is locking stuff down.
On this very same machine (Win 7 Pro), I've got a Virtual Machine running (Win 10 Pro) and TeamViewer works PERFECTLY inside of that VM.
Just wish I knew what else to try.