Check whether every device has the problem

The first step is figuring out where the issue actually is. If the internet is down on every device in the house (phone, laptop, TV), the problem is with the router or the provider. If it's only on one device, the issue is with that device's settings specifically.

If it's not working on any device

Restart the router — unplug it for 30 seconds, then plug it back in. This resolves most temporary glitches.

Check the indicator lights on the router — if the internet indicator (usually labelled WAN, or lit red / not lit at all) differs from the others, the issue is likely on the provider's side. In that case, it's worth calling your internet provider's support line.

If it's only affecting one device

Forget the Wi-Fi network in that device's settings and reconnect by re-entering the password. Sometimes switching to a public DNS server (such as 8.8.8.8 from Google) helps — this can be set in the network properties.

If nothing helps, the issue may be with the Wi-Fi adapter driver on that specific device, especially after a recent Windows update.