You need to edit your host file. You have used TU. It changes your host file to point Itunes to cydia instead of apple for the signing/authorizing of the firmware.
You can either run TU and press kick out of recovery mode. OR edit your host file. comment out the line that has XXX.XXX.XXX.XXX apple.com.gs. or something close to that.
Make sure the line 127.0.0.1.aplle.com.gs is NOT commented out.
commented out is the number sign in front of the line "#". it tells the computer to skip that line.
there are direction on Iclarified.com on how to edit your host file.