Can't login

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I have had Teamviewer working on my desktop computers, two Win 10 and two Linux boxes. I have assigned them to my account and I perform remote control and file transfer between any two of them. However, when I try to control my Android tablet, it appears to connect but then says to goto login.teamviewer.com on the PC to connect to the tablet. When I attempt this, it asks for my login and password but when I enter it I get the message that I have to add the device to trusted devices. The PC is already a trusted device but I try adding it again. It doesn't work. No matter how many times I try to add the device the login STILL says it isn't a trusted device. I've tried from another computer and using different browsers but NOTHING works. What am I doing wrong???