This extender (model RE450(EU)) worked fine for a year.no settings changed on house router. Some additional wifi devices, but not many.i disabled these for the test. Now  RE450  cannot maintain a stable extended wifi connection. The wifi connection is continuously going up and down.The wifi devices are losing and reconnecting to the extender. No more wifi devices than usual (tether reports that there are 3 clients).Tether itself also loses connection and then regains connection even when i am 50cm from the device.The SSID is different to main router.

The lights on the RE450 device display everything ok (solid blue). We only use 2.4G .

main house router is working fine. - internet available via both its ethernet  and wifi connections. it is a totolink router and has not had its firmware recently upgraded.

i have powered off all devices and house router and extender, and then powered them back on. No change in behaviour.

The wifi connection is unstable for both android devices and window laptop devices.

There appears to be no recent firmware update available for the RE450 v4, so i am veering towards the conclusion that the device has failed and is not fixable.

Has anyone had this problem and been able to fix it, or did they just replace the device with a more reliable one?

Thank you.