Good afternoon and thank you for posting on the Final Fantasy XIV Technical Support Forums.

A VPN will route you through a private network as opposed to your ISP's network. Generally, they sacrifice speed and stability in favor of privacy. As such, they may create difficulties when connecting to various services. You don't seem to have any connection issues with the VPN off, so it sounds like it's causing the instability. Unfortunately, I don't know much about that particular VPN, but you could try adjusting some settings to see if it will let you connect. Other than that, I'd recommend leaving it off when you play the game.

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