This is very simple just type; Google Adsense Sandbox in the search bar and you will see many results. But the first one with the title: Google AdSense Sandbox - Google Ads Preview Tool
Open the website and enter the domain that you want to check and select the region. Press the submit button. If you see blank results, then the domain is banned on Google and Google AdSense.
Hope this will help!
Gustavo Woltmann.