The device itself may be deleting the cookies/cache automatically depending on your settings.
When googling 'a53 Samsung retain cookies', Google provides some steps on settings to check to see if these are automatically clearing the data files, which TVGO needs when restoring the device registration. Some of these steps are to check if 'Clear browsing data on exit" or "Block all third-party cookies" within your browser's privacy and security settings are enabled.
These settings will depend on the browser you're using. It may need a little play around to get your settings right.
We aren't able to support third-party devices, but we'll help in any way we can.
Keep us posted with how you get on.