When does this occur?
This is an error that happens due to the game server and the region's ISP not establishing a stable connection. This can happen regardless of having no internet issues with other games or services.
What can you do to resolve this?
The only known solution is to use a VPN to bypass the region block that is happening between the game server and ISP.
Players have stated using the free service CloudFlare One Client (formally known as CloudFlare Warp) has helped them secure a more stable connection and allows them to connect to the game.
Other users have opted to go with paid services like NordVPN and also have had a high success rate.
For details on how to setup either of these VPNs, visit their respective support sites: