lost internet connection. Airport and iMac working

Hello there Frances262,

Thank you for using Apple Support Communities!

This could be caused by any number of things, and I have a great article to help troubleshoot the issue here.

Named iOS: Troubleshooting Wi-Fi networks and connections found here http://support.apple.com/kb/TS1398.

Start with the troubleshooting at the top:

1. Be sure that you are in range of your Wi-Fi router (access point).
2. Tap Settings > Wi-Fi and turn Wi-Fi off and then on again.

   If unable to do so, see this article.

3. Confirm that your Wi-Fi router and Cable or DSL modem are connected to power, turned on, and indicate that they are connected to the Internet.

   If not, refer to your network administrator or ISP for assistance.

4. Restart your iOS device.
5. Tap Settings > Wi-Fi and locate the Wi-Fi network to which you are connected. Then tap > and Forget this Network. Try to connect to your desired Wi-Fi network again.

   Note: You will need to enter your Wi-Fi password again if your desired network requires one.

6. Turn your Wi-Fi router off and then on again². If your ISP also provides cable or phone service, check with them before attempting this step to avoid interruption of service.
7. Update your device to the latest version of software.
8. Update your Wi-Fi router to the latest firmware².

   For AirPort Base Stations, see this article for information about firmware updates.

There are more troubleshooting steps down toward the bottom based on what the symtpom is, choose which symtpom fits the issue and follow the directions therein.

Unable to locate a Wi-Fi network

Unable to connect to a Wi-Fi network

Wi-Fi disconnects, or signal strength is less than expected

Unable to access the Internet while connected to Wi-Fi

Unable to automatically connect to Wi-Fi

Regards,

Sterling