"The internet is down" covers a lot of different problems, and only some of them are the internet. Five minutes of checking will usually tell you whether to call your internet provider or the people who run your network — and it gives whoever you call a head start.
1. Is it one person or everyone?
Ask two other people — ideally one on Wi-Fi and one on a cable. If it's only you, it's your computer or your desk, not the internet. If it's everyone, keep going.
2. Does anything work locally?
Can you print? Can you open a shared folder or reach a server in the building? If local things work but websites don't, the network inside your walls is fine and the problem is somewhere between your firewall and the outside world — that's usually the ISP or the equipment on the edge.
If nothing works, including local things, the problem is inside: a switch, the Wi-Fi, or a core device.
3. Look at the modem or router lights
Find the box the internet provider installed and, without unplugging anything, look at the lights. Most have an "Internet," "Online," or globe indicator. Green is usually good; red, amber, or off usually means the provider connection is down. Take a photo of the lights — it's genuinely useful to whoever you call.
4. Try a phone on cellular
Turn off Wi-Fi on your mobile phone and load a website. If it loads on cellular but not in the office, the office's connection is the problem. If it doesn't load on cellular either, there may be a wider outage — check the ISP's status page from your phone.
5. Power-cycle only the ISP equipment — once
If the lights say the provider connection is down, unplug the modem (the box the ISP owns) for thirty seconds and plug it back in. Wait a few minutes. Don't reset anything else — firewalls, switches, and Wi-Fi controllers are configured on purpose, and a factory reset button can turn a short outage into a long one.
Then call, and say what you found
"Everyone's down, local printing works, the modem light is red, and cellular works" is a report that points straight at the ISP. "Nothing works, not even the printer" points at the network. Either way, include your account number if you're calling the provider, and a callback number that isn't the office line.
If we run your network, send us the same summary and we'll take it from there — including dealing with the ISP for you.