Sonoff devices dropping offline

I have several Sonoff devices in my home:

  • 2 x RF Bridges (both flashed with Tasmota)
  • 1 x Zigbee Bridge (flashed with Tasmota)
  • Basic R2 wireless switch
  • S26 R2 wireless switch.

In the last few weeks two of the devices, which are located about 12 feet from each other, have started dropping off the wireless network regularly, and will not reconnect even after a power cycle. The problem seems to resolve itself after a few hours.
The two devices in question are the Basic R2 switch and one of the RF Bridges. All of the other devices are fine.
Both of the problem devices are connected to the same wifi access point in the next room (about 15-20 feet from both devices). The access point is a BT Whole Home Wifi disc, connected directly to my broadband router via ethernet. None of the other devices connected to it are having any problems.
Has anyone else had similar issues with Sonoff devices? Any ideas for how it can be diagnosed/fixed?

whats doing the DHCP ing

that happened to me when I had a router supplied by telo they are cheap

Im using the ADGUARD plugin and that is my DHCP server

The only problem is you need a have a way to get out the router when HA is down

in the 6-8 months only been down once was a hard drive failure hard

Usually when network devices drop offline at seemingly random periods, it’s frequently an IP address conflict. The device won’t reconnect after a power cycle because the router remembers the MAC address. Even if you have set a static IP address (which I do not recommend).

The DHCP server in your router keep a log of IP address assigned to MAC address. Sometimes in non-volatile memory. How long the logs are maintained depends on your router.

Have you tried rebooting the router?

DHCP is handled by a Netgear X4S R8700 router. I do allocate static IP addresses for many devices that need direct access from applications running on the network - e.g. IP cameras, Broadcom remote control devices, etc. I usually set the static address on the device if possible, but if not I use address reservation on the router, using the device MAC address.
So this morning the Basic R2 switch was back online (without any intervention from me), but the RF Bridge remains offline (with the blue LED flashing). I have cold booted the Netgear router (and also my ISP router (Virgin Media Hub), for good measure. I also power cycled the RF Bridge. The blue LED eventually stopped flashing, but I’m getting 50% packet loss when I ping it, and I can’t connect to the web UI (it times out).
The IP address conflict theory is interesting, but I don’t understand how it can be happening, as a ping of that IP address fails when I disconnect the RF Bridge. In any case, I have changed the reserved the IP address allocation on the router to an address which I know to be free, but the symptoms are exactly the same - 50% packet loss on pings and still unable to access the web console.

So a third device has now dropped off the LAN. I’ve just realised the common factor - they are all connected to the same disc in my BT Whole Home Wifi setup. The disc in question appears healthy, according to the BT Whole Home Wifi app (it says “good connection”), but I restarted the whole system anyway from the web interface.
All devices came back online, but only two of them reconnected to the original disc. The RF Bridge was one of them, and is still seeing 50-75% packet loss on pings. The other device also has a very poor connection (I can’t access it from the associated app).
I’ve power-cycled the disc in question, but it hasn’t helped - I have exactly the same problem with both of the devices connected to the disc.
The location of the disc has never changed, and no new electronic devices have been introduced anywhere near it. Maybe the disc has developed a fault???