I have exactly the same problem! Recently I bought another computer so I can keep my data at home and use the laptop to travel and access the one at home. So I installed and setup Team Viewer on both computers with the same account, and since then it was working for about a week,than it started to promt me about a password when I try to connect my home computer,wich it didn't ask before. I log in automaticaly, so I tryed to change the password for my account but I couldn't, because it was wrong password I was entering. So I requested forgotten password change and changed it, but it still promts me and sais "The password you have entered is invalid, please try again.".When I enter my account password in the empty field it goes away but in the box for the status it says"Connection not established"
Tell us about the setup on both ends - how did you connect before?A password recovery for hosts is not really necessary, as you can simply set a new password. And i think i wouldn't like it, if my passwords could be recovered remotely.