All I can say is when I had NextDNS configured on my router it blocked requests to some IKEA domain, possibly smetrics.ikea.com from a cursory search through he

All I can say is when I had NextDNS configured on my router it blocked requests to some IKEA domain, possibly smetrics.ikea.com from a cursory search through he logs, and my Tradfri gateway would just straight stop responding to anything at that point. I googled around for a while and found other people having issues with DHCP and QoS with Tradfri gateways, so I made sure it had a static IP set as well as all QoS “features” being disabled, but this didn’t help. It would work at first, for some period of time (30 min maybe?) and then stop responding. Once I saw the blocked DNS lookups I disabled NextDNS on the router and flushed any caches on the router, rebooted everything and it’s worked fine now for a good month or so. I will admit I haven’t done any further investigation, but simply concluded that the gateway at some point started phoning home and if it didn’t receive a response went into some catatonic state. Maybe I’ll dig deeper at some point, time permitting.