your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network - Apple Support
- Turn it off and on again. First try disabling/re-enabling WiFi, then restart entire system.
- Remove WiFi network from list of those remembered (forget), then when reconnecting it will be treated as a new network.
- Install all current OS updates (Windows, Mac, Android, iOS).
- Disable competing WiFi broadcasts
- Printers. Many WiFi printers are enabled from the factory for DirectPrint WiFi broadcast, which is almost never used, and which makes it harder for your device to connect to the real WiFi.
- Personal routers and access points
- Mobile phone tethering (hot spot)
- Update WiFi drivers from the manufacturer’s support site. Reinstall even not newer than the installed version.
- Update system BIOS (also from manufacturer’s site).
- If the WiFi is made by Intel and the drivers from the manufacturer's site does not solve the problem, use the Intel® Driver & Support Assistant to update WiFi drivers.
If your Mac doesn't connect to the Internet over Wi-Fi - Apple Support
iOS (iPhone, iPad)
If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network - Apple Support
Wired (Ethernet) Troubleshooting
Try the following troubleshooting steps in this order:
- Turn the computer off and on again.
- Replace the network cable(s). Cat-6 is the best option. Cat-5e is acceptable. Cat-5 (without the "e") and lower should not be used.
- Test network connectivity with a different network wall port. It is possible that the infrastructure cabling or wall port is faulty.
- Try a USB network adapter. It is possible that built-in network adapter is faulty.