Samsung Galaxy A2 Core, Android 8.
Can connect to the phone with TeamViewer (version 15.1.3937) on Windows 10 and see the dashboard and list of apps, but can't control the device remotely.
Thank you for your message.
I recommend you to uninstall the TeamViewer QuickSupport app on your device and to reinstall the latest version from the Play Store.
Let us know if this has helped.