If you are logged into your device with a Google account but see this message, you may need to adjust a security setting.
Enable Sign-in prompts in your Google Account settings. This allows Google to securely connect your device to Concepts for sign-in.
Open your Google Account settings in a web browser. The page can be found here: https://myaccount.google.com/connections/settings
Verify that the toggle for Sign-in prompts, which reads Allow Google to display a sign-in prompt on Android, is turned on (enabled).
Then, try signing in to Concepts again.