Step 1: reboot all devices on the network: computers, router, cable modem (or whatever equivalent device your router plugs into). If that doesn't fix it, below

Step 1: reboot all devices on the network: computers, router, cable modem (or whatever equivalent device your router plugs into). If that doesn't fix it, below is how I'd proceed. Use the trace route networking tool (google it, different syntax on different OS) to some known good public IP address. I usually use 1.1.1.1 or 8.8.8.8. This tool shows you the path your traffic takes: $ traceroute 1.1.1.1 traceroute to 1.1.1.1 (1.1.1.1), 30 hops max, 60 byte packets 1 192.168.1.1 (192.168.1.1) 1.286 ms 1.386 ms 1.963 ms 2 192.168.11.1 (192.168.11.1) 2.591 ms 4.342 ms 5.219 ms ...snip... 16 0.ae19.GW8.CHI13.ALTER.NET (140.222.230.223) 42.888 ms 35.742 ms 0.ae20.GW8.CHI13.ALTER.NET (140.222.230.225) 41.060 ms 17 152.179.105.202 (152.179.105.202) 51.913 ms 50.681 ms 55.442 ms 18 one.one.one.one (1.1.1.1) 70.087 ms 65.130 ms 53.607 ms The snippet above shows that I have two local devices (192.168.1.1, 192.168.11.1) my traffic passes through and 18 devices total before my traffic hits the public IP. Run this command at 3:39. Then run it again at 3:40. Then again at 3:41. Compare results and that should give you a good idea which device is malfunctioning at that time. Some routers also have a ping command baked into them. If you can make it constantly ping 8.8.8.8, while you run the test above, it may help you. In the case where your traceroute stops at your own router, you can look at the ping from the router itself, and see if it also stopped: A) If the traceroute stops at your router, but the router ping is not interrupted, then something in your router is flaking out. B) If the router ping is also interrupted, then the problem is "upstream" from you. Maybe the cable modem (or whatever device) that is upstream from your router. If you decide the problem is upstream, contact your ISP. If it's local, investigate and/or replace the flaky device. HTH.