Greetings pocketokun,

We would just like to clarify that this error could be caused a connectivity issue. As you've mentioned that you've already tried other connectivity troubleshooting, this could be caused by the specific routing that your system is using to connect to our servers.

We would like to suggest the following troubleshooting steps:

- Please make sure all background applications (including anti-virus programs such as Norton, Kaspersky, Windows Defender, etc.) have been disabled and/or closed to minimize game interference before attempting to log in.
- Within Microsoft Edge, click the "Settings" option on the top right of the browser (under the three dots shown) and go to "Privacy, Search and Services" and go to the "Tracking Prevention" section. Make sure it is turned on and select the "Balanced" option.

Additionally, if any settings have been changed overall, it is best to keep things at default which you can perform manually by using the "Reset Settings" option under the "Settings" tab. Lastly, please ensure that Microsoft Edge is up to date by using the "Settings" > "About Microsoft Edge" option near the bottom left.

If the suggestions provided above do not resolve the issue, there may be a communication error. Please do not hesitate to reply back to this thread for further assistance.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!