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

I am very sorry for the trouble you're having logging in. Error Code FFXI-3101 indicates a transmission error with the lobby server, which typically means your game client is struggling to maintain a stable connection during the login process.

To help get you back into the game, you could try a few common fixes:

Power cycle your router and PC to refresh the connection.
Check that PlayOnline is allowed through your Windows Firewall.
Ensure DirectPlay is enabled in your 'Windows Features' if you are on Windows 11.

If you have any more questions or concerns, please post again in the technical support forums.

Thank you for visiting the Final Fantasy XI Technical Support Forums!