Resetting the Router
While you have an Internet browser connection to your router - in order to administer your router - take screenshots of every settings page. Prepare to perform a complete reset of the router.
If you cannot find your router's manual, try connections in this order:
http://192.168.0.1/
http://192.168.1.1/
http://192.168.0.50/
http://192.168.1.50/
http://192.168.0.5/
http://192.168.1.5/
http://10.0.0.1/
http://10.0.0.2/
Default factory admin username and password combinations for routers:
admin / (blank)
Admin / (blank)
admin / admin
Admin / Admin
admin / password (use that text string)
Admin / password (use that text string)
If you cannot find the RESET button press-in-and-hold time duration, count to 30.
Go thru a RESET with the Power cable plugged in (and all other cables disconnected); and after the router settles down, instead of restoring settings, do the following:
Unplug the Power cable and unplug all other cables. Press and hold in, the RESET button for double the manual's suggested amount of time.
After that, plug in the Power cable and let the router do its thing and settle down. Followed by connecting a direct Ethernet cable between your PC and the router. Followed by you restoring the router's settings. Followed by connecting any other cables to the router.
Make sure that your Local Area Network router has a complex administrative password.
Make sure that NAT is enabled on your Local Area Network router.
If you are able to select a Wi-Fi channel for your Local Area Network, start with Channel 1 and leave it for a while. It tends to be the more durable Wi-Fi channel.
Yet, you may find that you have to keep at the Wi-Fi channel testing, to find the channel that is the more durable for your Local Area Network, given the structure of where you reside plus neighboring wireless signals.
Be prepared to switch to an all-wired connection between your PC and the router, when your Wi-Fi appears to not work (as you stated). In other words, test wired vs. wireless.
Recently I experienced a strange problem when trying to log into my router. I tried using my usual Firefox browser, and got a security alert which blocked me from logging in. Switched to Brave, and had the same problem. Finally tried Pale Moon, and got in without a problem.
Network Toolbox Net security (title at the App Store)
Network Toolbox (for iOS) Review (article at PCMag)
NET Toolbox has a tool called Network, by which it will scan almost any network that you designate, and find other network devices.
For example
Let's say that your home LAN subnet is 192.168.0.0, and your modem's and/or router's IP address is 192.168.0.1 - usually the gateway IP.
In NET Toolbox, you could search the IP address range: 192.168.0.0 to 192.168.0.255
Yet you may be curious to find, what other gizmos might be using your LAN gear, and search a broader IP address range: 192.168.0.0 to 192.168.1.255
These searches can take some time.
Don't be surprised to find that some feature of your MODEM, has a different LAN subnet IP address of its own. For example:
Though you have your MODEM's router-side set up to use LAN subnet 192.168.0.0 for your home, and "everything works," the MODEM might also be using a different LAN subnet 192.168.1.0 and IP address 192.168.1.249 --- as an address to which your ISP tech support may connect, during a scheduled in-house visit.
The tech. guy can read several UP and DOWN -stream connection and data flow activities.
In order for you to read that info, at that unique LAN subnet IP address (192.168.1.249 in our example), your computer, sometimes, can be the only connection via Ethernet cable, directly to your modem, thence to the Internet. And - for observation/testing - you would have your computer's LAN settings arranged to use the same diagnostic subnet: 192.168.1.0 (set your computer's IP address, in this case, to 192.168.1.40 or 192.168.1.42 or something like that) --- focused upon reading what the MODEM has to say.
Some ISP's will guide you on doing that, over the phone. So that you can report what you see, while their tech guys fiddle with something at their end of the ISP's gear.
In other words, some modems have TWO default LAN IP subnets. One that you see and adjust for your LAN; and the other for diagnostics.