Apple iPhone App is a blank screen

I am trying to access home assistant on my phone to turn on my lights but the app is showing a blank screen. Any suggestions or is the app no longer supported?

It’s still there but can freeze sometimes.

Did you kill the app and restart?

I did not. I’m afraid I don’t have the password information as this is something my husband set up and he’s unavailable to assist me. Is there a way to try to login online to make sure I have the information necessary before I delete the app and reload? I am unable to find a telephone number for assistance. And I am billed each year $65 for the service.