I have just upgraded from TV-11 to TV-12, as required by the automatic update program, and therefore Teamviewer does not work anymore.
It says "check your internet connection. You probably use a proxy and should enter the necessary information in the option window".
BUT TV-11 worked perfectly before it asked for this upgrade, I have changed nothing, and all my other programs still run pefectly.
What should I do ??
My O.S. is W10 Professional.
I had this problem on windows 10......
went into task manager
found a running teamviewer task and ended it
started teamviewer again and it seems to work.