Nest gen 3 stopped connecting to WiFi

[e6Pete]

I have 4 Nest gen 3 learning thermostats with Heatlinks, three are working fine and have done for a couple of years now. However, one of them I found was disconnected from the wifi and I have tried everything to get it to reconnect and it will not see my network.  It was working fine for the first 12 months.

I have restarted the wifi, although the other three connect fine this one will not. I have allowed it to run out of power and recharged and restarted it to no avail.

I have started to look for a replacement but in the UK it seems they want to sell me a HeatLink as well which I do not need - just the thermostat.

How do I resolve this - winter is on the way her win the uk and there is a **bleep** of the house that will not have heating?

[Frustratedddd]

Sadly it's a problem that does come up, but do you have any error code on the screen or app?

Have you tried resetting Network in settings a couple of times. Do that twice on the trott, and see if anything helps? Try also updating software in settings, that sometimes wakes the wifi up. I would 99% think it's the wifi chip gone faulty.

Displays can be found on Ebay, and I list them on occasions.