To log out of FINAL FANTASY XI on a PlayStation 2:

Press the SQUARE button to access the main menu and select "Log out" (There are multiple menus within game, select left or right on the D-Pad or Analog stick to access the proper menu)

NOTE-
You cannot log out by pressing the "PlayOnline" button from the Main Menu because it only temporary returns to the PlayOnline. In this case, select the "Return to game" and return to the FINAL FANTASY XI game, then choose "Log out" from the Main Menu to return to the PlayOnline viewer.

To log out of PlayOnline Viewer on a PlayStation 2:

Select the "Exit Viewer"option from the PlayOnline Viewer.

If you are having trouble logging out of the PlayOnline Viewer:

-Confirm a connection with the PlayStation 2 and the internal hard disk drive

-Confirm if the indicator of the PlayStation 2 is and the HDD turns on. For further information, please refer to the manuals

-Check if the communication equipment is promptly connected. Please confirm the connections of modular cable and LAN cable with maker's manuals

-Update the communication equipment firm-ware.
Updating the firm-ware can help fix a log out problem. Please refer to the manual or contact the maker for firm ware update information

-Change MTU value
Changing the MTU value may fix log out problem. Please change the MTU value setup, which is at the Auxiliary Settings in the Network Settings