Board Thread:Questions and Answers/@comment-36181913-20180713192720/@comment-33362357-20180806003339

That's the common server connection error. Check your Internet connection. It could even be your Internet provider blocking your connection to FGO. In that case, use a free VPN service (ProtonVPN). You don't need to be constantly connected via VPN, and I recommend against it. Anyway, connect to a VPN server and then start FGO. If it works, then your Internet provider is doing something strange.

The other thing to check is your wireless connection and your router settings. Your router might be blocking FGO JP traffic.