Oh. If you are talking about VN Meido. I assume it is because of security reason. Ex, prevent of hackers by tracing IP address(only you and the admin can see this), prevent bot, etc.
PS: After checking the website, for me it is not privated. So I can see all the content even in guest mode. Most likely they could have banned or blocked your country. Could be something else too.
If this doesn't make sense. It is either I have no idea what website you are talking about. Or I am lost on what we are talking about.
Also, I go on VN Meido twice a week to check for updates and to upload it here.