Mysterious 90001 into 5006 Error combo

So a problem I've seen sometimes is, typically when visiting worlds, but in other conditions sometimes as well, the game will freeze and then instantly disconnect with a 90001 error. When trying to re-log, the game gives a 5006 error and kicks to desktop.

Using PingPlotter, I identified no packet loss going on at the time of the disconnect, nor any other signs of the internet going out for any given length of time. Is there a known cause to this specific error combo above? And if so, how is it prevented?
(Edit: Fixed transferring to visiting. So there's no confusion between World Visit and actually transferring a character to a new home world.)

Good morning and thank you for posting in the Final Fantasy XIV Technical Support Forums.

Please try the following troubleshooting steps:

- The game will use the Internet Explorer web browser to connect to the internet. Open Internet Explorer, then open the "Tools" setting, go to "Internet Options" and adjust the following settings:
- Under the "General" tab, please delete ALL browser history.
- Under the "Security" tab, please move the slider to the lowest possible settings or no higher than "Medium"
- Under the "Privacy" tab, click “Advanced” and select ‘Accept’ under both First Party and Third Party Cookies.
- Under the "Advanced" tab, please make sure that "Allow software to run or install even if signature is invalid" is CHECKED.
- Make sure that all SSL and TLS (EXCEPT SSL 3.0) are CHECKED. [SSL 3.0 should be UNCHECKED]
- Hit "Apply" to save the settings, and then "OK, to close the Internet Options menu.
- Please RESTART your PC now. Once your PC has been restarted, Right-Click the FFXIV launcher icon once more and select "Run as Administrator"

-Make sure your fire wall or antivirus program is not interfering with the game

- Check to see if the following port ranges are opened on your router. You can contact your ISP and request they open them for you:
▼TCP
54992 through 54994,
55006 through 55007,
55021 through 55040

-Try disabling background applications and do a clean boot by opening the task manager and selecting the “Start up” tab. Disable everything and then restart the PC.

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Okay, I will try this to see if this improves reliability overall. Previously, all of the Internet Explorer options were already set such at the time of the disconnect, so it should in theory fall to restarting the PC and running the launcher as administrator.
FFXIV is also currently set as an exception in Windows Defender/Firewall, so it also leaves checking port ranges for non-IE settings.

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Due to no response from the original poster, this thread will be moved to 'Closed Concerns.' If anyone is still having this particular problem, please create a new thread and we will assist you in any way we can.

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