I think I remember. I emailed the public certificate and then installed it on my iPhone from within the mail app. Then you have to go into general then profiles and trust the certificate. Then I went into the HA app and connect to https://hassio.local
I think getting the trust button to show can be an issue.
Then try logging in without the port after your IP address in HA. Also try hassio.local port number as well.
Failing that I would try removing the certificates you’ve imported and try again. If you can’t manually remove them you may have to reset network settings, but of course that will reset all the network stuff on your phone.
Failing that I’m afraid I’m fresh out of ideas as my setup uses LetsEncrypt and an external domain so it’s a very different setup.
I thought I’d jump into this thread and say I’m experiencing the same issue.
I set Home Assistant up to use a self signed certificate. All works fine from my Mac when I hit either https://hassio.local:8123 or the IP address of the instance, but when I try to do it from the iOS app (or any iOS browser for that matter) I get the same result as reported in the above posts.
I set the logger to debug mode, but there was literally nothing in it related to logging in. Is there a different way to output some logs for this?