"The support team suggested that I check it has a good ethernet connection?" Were you told that on a Friday at 4:30 PM? First off that would work if the ethernet in question was hard down. But your issue is fixed by a reset tells you there was something wrong. That's all. When you were told to check the ethernet connection you should have asked which one. And wired backbone means what? How many eero's and types are in your network? Document your steps after troubleshooting and fixing. Did your app tell you anything?