Check your device is compatible with Disneyplus.com/begin. Navigate to your device's firmware settings page and check for updates. Try deleting and reinstalling the Disney+ app from your device's app store (e.g. Google Play or App Store). Try logging in with the same details on a different compatible device. Make sure the device is compatible with Disney Plus, and if it is, restart it. Check for driver and system updates, and if all else fails, reinstall the app. If possible, try using Disney Plus on another device.