@Buddha1059 Connect a pc direct to the modem and see if it works. Be sure the isp supplied modem is in bridge mode if it has one. You may need to power off both the modem and router, unplug them,...

@LinuxNerd14 So the issue is before the router. Sign on to the modem and check its settings. You may need to google on how to set it in bridge mode.

@Niki113 One of first test is to connect a pc direct to the modem and see if you have the issue. If the trst is good, then connect the router and see if it is Ethernet only or wifi only issue.

@LinuxNerd14 I assume the modem is in bridge mode and not transmitting wifi or anything on the Ethernet ports except the router. Does the modem have multiple ports as it may require a specific one...

@LinuxNerd14 Sounds like the router is not getting the ISP's IP address. Sometimes the modem will not release the previous devices address. Try power off and unplug both the modem and router, wait...

@New_TPL_User one thing you could do is use address reservation for all of your known devices. Then when a new one is added, you can see the ip is not one of the reserved addresses. Better info in...