configuring wpad give me 0x8007054B error

I've Domain Controller and TMG server(2010 standard edition)... The both is windows 2008 server.

my problem is when I'm going to configure "Web proxy auto discovery"

display error 0x8007054B

1- Testing by tmg's Troubleshooting this link http://firewall.xco.local:8080

2- Testing by tmg's Troubleshooting http://firewall.xco.local everything is OK.

I Don't have any idea how to fix that problem .

It looks like the device at firewall.xco.local is simply not listening on port 8080, or port 8080 needs to be opened in a firewall. Check your configuration.

If you can fetch http://firewall.xco.local/WSPad.dat (or http://firewall.xco.local/wpad.dat), and it is the configuration you want, specify that as your proxy autoconfiguration data. If you need it to come from the service on port 8080 you'll have to ensure that service is operational and can be accessed from all your client PCs you want pulling WPAD data from it.