Nighthawk RAX20 - Connected devices stopped communicating (not guest network)

Nighthawk RAX20

Firmware Version V1.0.11.112_2.0.77

About a month ago I noticed the devices on my home network had stopped communicating with each other, for example; I could not cast YT or Netflix to a Chromecast from my Pixel 6 phone, I couldn't stream Spotify to any smart speakers, and I couldn't connect to my Hisense TV (which does not use Google).

At the time, I thought it may have been due to upgrading to Android 13 as the issue occurred on the same day, however, my partner's iPhone and iPad (iOS 15) also lost this same casting functionality. I will point out that all the devices I am trying to connect to are on my main network (not guest) and I am using Smart Connect functionality on the router.

I tried rebooting phones and devices on the network with no luck, I factory reset a Google home device and could not get it set up again, receiving a message to 'disable AP isolation' on my router. Eventually, I rebooted my Nighthawk RAX20, lo and behold I could now see all my devices again.

Skip forward 24 hours and again I've lost communication with everything after doing nothing new, I decided to try something I had no expectation of working, I edited my Guest Network Settings and checked the box to allow guests to see each other and access my local network, unbelievably, everything came back and has been stable for over 24 hours.

My hypothesis is that there may have been some update to the router that has mixed up guest network settings with my main network, in such a way that devices could no longer communicate until I changed this setting.

In a day or 2 I will revert these guest settings on my router to see if the devices lose communication again. It would be great if anyone else has come across this issue so I can stop pulling my thinning hair out.

Cheers,

Meaty