Can connect to one machine but not another that is working fine with Android TeamViewer

I am having a problem connecting to one machine with my PC that shows available.I can connect fine to a friends remote PC. I can also connect to the problem machine fine with my Android phone version of TeamViewer. I have rebooted both my PC and the remote machine with no change. I have also un-installed and re-installed TeamViewer on my PC with no change in behavior. This problem just showed up today, I was on the remote machine yesterday just fine. I have a commercial license on my PC. This is getting old fast, I really need to get this fixed.

Thanks for any help or advice!

Jerry Hubbell