a fop2 server debug won't help in this case. Your problem is NOT in FOP2 (the switchboard). Your problem is with the FOP2 Manager that is a simple php application, and separate from FOP2 server itself.
You must look at php logs, you can enable debug in config.php and you will see debugging warnings and errors on screen. You can also inspect your web server error log file as it might be logging php errors or similar there.
Do not look at fop2 server debug logs, not even at the javascript console debug when you connect to the switchboard, as it has nothing to do with the fop2 manager plugins page unable to reach www.fop2.com via port 80.
Best regards,