An VPN is a service which encrypts data from your internet connection. It is therefore inaccessible from your ISP. Sometime, ISPs block online services and websites. The reason for this is security motives. It's an issue that is common in countries with strict censorship. The solution is an VPN. https://trevorsvvus.shoutmyblog.com/12884820/5-simple-statements-about-vpn-explained