Try power cycling your modem.
Turn your devices off. Unplug the modem. Wait for at least a minute, then plug the modem back in. Then, after waiting for at least five minutes, try connecting a device via WiFi.
Try power cycling your modem.
Turn your devices off. Unplug the modem. Wait for at least a minute, then plug the modem back in. Then, after waiting for at least five minutes, try connecting a device via WiFi.