If the instructions above do not help, please try to completely uninstall your FireWall TEMPORARILY. Disabling the firewall is not enough, because FireWall keeps blocking access even if you switch it off. After uninstalling and rebooting, check if your problem persists. If it is resolved, then the problem is definitely caused by your FireWall software. You should try to contact its developers, and ask them for a solution, or try another FireWall.