According to the manual for your specific router,m it should be under advanced wireless.

It's most likely called AP isolation. You can find it in Advanced > System Tools > System Parameters > AP Isolation. My Chromecast wont work if it's enabled either, because it basically blocks wifi...

Archer C1200 .. It's dirt cheap but it delivers.

I'll bet my left nut that it isn't the router, but rather Windows causing issues. I had this issue as well. Try this; 1) Open the command prompt (cmd) as admin and type netsh winsock reset catalog -...

ShieldsUP! by Steve Gibson. https://www.grc.com/x/ne.dll?bh0bkyd2

Testing my routers firewall today and it seems whenever it's set to optain time automatically, port 123 is closed (a.k.a. actively responding to requests) instead of NOT responing to requests. I'm...