I just finished doing this, and everything seems to go well but alexa doesnt find any devices at all. I cant add anything to your request, hopefully someone can come help us both
UPDATE – 24th of May 2020
Compared the haaska procedure with the Manual integration procedure, (and also noticed a recent update on the official HA integration/Alexa doc. I followed it again and it worked. Key change for me was selecting the right region (in my case being based in Australia, the instructions point for using the Oregon region for my Lambda function).
All OK now as per HA Manual Alexa integration approach.
Legend!!!
I’m still having the same issue; test works, but discovery doesn’t. I’ve double-checked my region and it’s set to N. Virginia (which is the closest to me)