Internet connectivity issue may occur due to various reasons but if you are using Norton Antivirus, than Norton firewall issue can be one of them. You can try to fix this issue on going on General Settings tab, next to Smart Firewall and click it slider turned it off after that in the protection alert box go from the drop down menu and click apply and then select permanently and click ok. If the problem still persists contact us at Norton Antivirus Customer Service .
http://nortonhelpus.com/norton-firewall-issues/
