i phone4s 12.7 GB

Would you please specify the issue? Do you have thew issue with wi-fi connection? If yes you may try this:

Try to reset your iOS 8 Network Settings, navigate to the Settings app, tap “General”, then navigate to “Reset” and choose “Reset Network Settings” This will force the device to reboot, and it also erases any wi-fi passwords you have saved, so be ready to enter them all again.

You may also find useful troubleshooting techniques here: http://osxdaily.com/2014/09/22/ios-8-wi-fi-problems-fix/