A few bottle of Advils not to mention when someone like me get in touch with their support staff, they either hang up the phone - or call me a$$ after case closed!!
First, it was my Unbound issue and certain Apple services! After a few months, I gave up!
Now, Cloudflare DoH vs ecobee smart thermostat access.
Basically, unless I disable DoH or use 220.127.116.11 or any other DNS, I cannot see my 3+ year old registered thermostat using browser and or ecobee App on my iDevices!!
Just thought sharing with those who may have similar issues. Don’t hate Apple, ecobee or whoever vendor you’re dealing with!!