Can not connect unless reinstall v12 again

Dear All:

Many users may have experienced that is bothering me a lot. after upgrading to v12 and with WIN10 system each time I open the Teamviewer I just could not connect and it shows the message the connection can not be established and sometime there is a pop up window saying the proxy setting issue etc. this will go back to normal after I reinstall the new v12 and everything turns to the way it should be.. I have been a Teamvieer user for long time and I just do not know how to close this vicious cycle. Any suggestion is appreciated for solving this mystery. KC