How-To Remove TeamViewer 14 From Ubuntu 18.04
Teamviewer 14 does not work on Ubuntu 18.04 at the present time. When connecting to a Headless Ubuntu Server using Teamviewer, you are prompted to login, yet your credentials do not work, and the login screen continues to loop with Login, and Invalid Password.
These steps will help you remove the product and replace it with a version or product that does work.
Use Putty locally on the same network your headless system is on
apt-get remove teamviewer
Now time to replace it with a product that works.