Solved Cannot access LAN???

I am getting rather frustrated with our new computer that runs Windows 11.

For the past several days, I was able to open Explorer and browse a shared directory on one of the computers on our LAN. I tried that today and was informed ‘Windows cannot access \\LAN_COMPUTER'. Absolutely nothing has changed on the LAN.

On the Windows 11 machine, I opened a cmd windows and tried ‘ping LAN_COMPUTER’ and was informed ‘ping could not find host LAN_COMPUTER ‘, but ‘ping ip_address’ worked just fine. I also ran ipconfig and confirmed that everything is correct. I went to Settings -> Network & internet -> Advanced network settings. Under "More settings", I clicked Advanced sharing settings and confirmed that Network discovery is On.

What on earth should I try???

Did the IP address of LAN_COMPUTER change? Run ipconfig on LAN_COMPUTER, and then “nslookup LAN_COMPUTER” on the other one. Make sure the addresses match. If not, “ipconfig /flushdns” on the other computer.

pseymour - Thanks for the prompt reply.

The IP address has not changed - on my router, I have created DHCP reservations for all devices on our LAN. I did run ipconfig on Windows 11 machine LAN_COMPUTER and the result is as expected. However, on my Windows 7 machine, nslookup seems to give silly answers for any computer name I enter. It even replied 'DNS request times out' when I gave it the IP address of the Windows 7 machine.

Who owns the router? Is it yours or your internet provider? Reboot it if it's not yours and try to get access to the internet again. Something has changed?

You can skim these two. Handful of possible solutions

Very weird - after rebooting the Windows 11 machine, it worked fine. Thanks all for your help.

Maybe the master browser changed??? After reboot it connected to the right one???