Good morning! Thank you for posting in the Final Fantasy XIV Technical Support Forums.

As the linked post suggests, typically the 90002 error usually means there is a connection issue or interference with the game's servers. However, as it appears the issue only occurs for one particular character, we would recommend trying out the following troubleshooting steps to see if it helps with alleviating the issue:

If this is only affecting one character, then it may be something to do with your locally-saved settings. Go to 'My Documents' > 'My Games' > 'Final Fantasy XIV' and delete that folder. Right click on the folder itself after deleting the contents, if it is set as read only, please uncheck that. If there are any corrupted files that are associated only with that character, this will get rid of them. Deleting these local files will not delete the associated characters. Please note however, this will reset all in-game configurations to their default values.

Aside from the above suggestion, please perform the following for best practice suggestions:

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.
Lastly, we suggest to power cycle the console and router by shutting down the PlayStation 4/Router and leaving the power supply unplugged for 5-10 minutes.
- Flush DNS: Within the "Command Prompt" of the device, please type the command "ipconfig /flushdns".
- Reset TCP/IP: Also within the Command Prompt, type the command "netsh int ip reset" and then restart the computer.
- Delete the Patch Folder: Navigate to the folder using this path This PC > Docs > My Games> FFXIV ARR > Downloads > FFXIV patch (Use for either the version update error or cannot download patch files error)
Then either rename or remove the folder, the next time FINAL FANTASY XIV is launched, the client will repair the folder.
- Change local DNS: Please try changing the local DNS server to 8.8.8.8 and 8.8.4.4