Back to the context, without a VPN I obviously can't access this casino, which is why I get a "404 not found". They explain that this casino is VPN friendly, but my country of residence isn't on the blacklist.
I decided to ask the support, they suggested to switch to the incognito mode of the browser or try to clear cache and cookies, but still not working.
Same here, I got 404 not found when I visited the site without VPN but it works fine when I turn my VPN on (I used Japan's IP). It seems that they block some countries although the countries are not on theri restriction list including my country. Anyway, funny to hear the suggestion from the support because it wont work since I believe it has nothing to do with cache/cookies. I guess it must be unexperienced support or a hired support from 3rd party services who do not really understand the issue.

as I said and supported by the screenshot, it shows the response from the chat support.
I'm still connected with them via chat and want to know how far they've come in resolving this issue, as most users are experiencing the same problem. A few minutes ago without a VPN, the "404 not found" display remained unchanged.