Access to the teamviewer server has been denied

Hi, When I start teamviewer i get a pop up box that says:

"Access to the teamviewer server has been denied!"

Tried restarting and re-installing but still getting the message. I've included the screenshot. Works fine everywhere else. Teamviewer has been running fine on my computer for a year or two then this started two days ago. I'm a fully paid up V10 user.