I've been having this error for 3 days now and I can't even reach the Character Selection screen because after accepting the terms of the game, I am greeted with the "Error Code: FFXI-3101 Transmission error with lobby sever".
"Have you tried restarting your modem router/PC/Steam/Windower/POL?"
Yes, all of them.
"Have you tried reinstalling the game?"
Yep.
"Is the opening CS disabled?"
It is.
"Is Client for Microsoft Networks installed?"
Yes, it is.
"Are the TCP: 25, 80, 110, 443 and 50000 - 65535 ports and UDP: 53 and 50000 - 65535 ports forwarded in your modem router and Windows Firewall?"
They sure are.
"Have you tried disabling the Firewall?"
Yes.
"Does your ISP blocks FFXI?"
No, they don't, I've questioned about this several times.
"Note that Proxy servers and satellite connections do not work correctly with FFXI."
I use Fiber, no Proxy.
"Have you tried using a VPN?"
Yep, Kaspersky VPN, with both Brazil, USA, Canada and Japan servers. Nothing.
"Have you tried using another connection or hotspot with your phone?"
Yep, same error.
"Have you tried using another computer?"
Yes, I have. Two, btw.
Therefore, I believe that the problem lies within my account. The last time I played FFXI I believe it was in February and I just can't accept the fact that I paid 70 Brazilian Real just to not be able to connect even to the darn Character Selection screen.