I had to reinstall iOS lately, and when I tried to login the iOS app, Integration couldn’t be created anymore. 
Tried this solution, but didn’t work as well.
The notify.[iPhone name] service doesn’t even appear in Developer tools / Services.
HA app works btw, the only thing I’m missing are the notifications.
Did you remove the old integration (from HA)? Next do you have a certificate?
Also check if you have default_config in your configuration.yaml if you don’t have that and don’t want it you could add mobile_app.
Please make sure that your HA instance is reachable and if you use something like nginx or IIS to enable websockets support
damn. the problem was not with those things.
didn’t follow your steps precisely. step 7 and 8 was pretty important. 
