Unable to access game. Error code FFXI-3001

I have been unable to access and play FFXI for the past few hours. I can log into the PlayOnline Viewer fine, and even make it as far as the Character Selection screen in FFXI, but once I select my character I get stuck on a black screen with the Downloading Data message displayed in the bottom right corner. The game stays on this screen for a minute or so before giving me the following message:

Error code: FFXI-3001
No response from the FINAL FANTASY XI server.
Connection timed out.
Press OK to shut down.

Does anyone know what might be causing this, or how I can go about resolving the issue? The game was working fine yesterday and I'm experiencing no other Internet-related issues. I've also run a file check for both the PlayOnline Viewer and FFXI and neither of them reported any errors.

this is usually a sign of either security software blocking connections from FFXI, or issues on the net causing connections to stall. If you have a router or software based firewall/security suite installed, check the logs to see if any traffic is getting blocked while you are connecting. If so, google the IP to see if it points to SE--if it does, you'll need to create an exception to allow that connection in your security software.

If it is getting blocked at the router, it may be easier to set up the port forwarding as per SE's instructions. You can test if port forwarding may solve it by simply bypassing your router and connecting directly to your modem. If directly connecting works, then it is an issue with either your router's config (ie: setup port forwarding or DMZ your PC, or posibly some security options like NAT security or internal firewall, etc. need to be set to lower levels), or possibly even your router is in need of a firmware update or is going bad and needs to be replaced.

If you find no traces of it happening locally due to your local security or router, you'll need to get your ISP involved to flush out the stalling connection issues. Have them trace these addresses from your modem (may be easier to copy/pase these in an email or online chat if that is an option):

square-enix.com (202.67.53.202)
SE's DNS servers (dns1.square-enix.com to dns4.square-enix.com): 202.67.53.31, 202.67.53.95, 202.67.53.32, 202.67.53.96)

ffxi00.pol.com (124.150.154.122)
c000.pol.com (202.67.54.52)

124.150.154.84 (one of many IP's the client links to in the background that don't have DNS names)