Was TeamViewer Backup previously installed on this device?
If so, it could be the last uninstall was not able to complete. Please unassign and re-assign the device to your account in the TeamViewer General settings (Extras | Options | General | Account Assignment). Once done, attempt the same installation again.
Should the issue persist, I would recommend reaching out to our support team directly for further troubleshooting.
Josh P. Senior Moderator
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