I’ve never PMed anyone on any platform and don’t know how.
I originally set up the Garadget app. on my Android phone and can still control my door that way, but when I want to control it from my Android tablet or from my Linux desktop, it asks me to log in. That makes sense, but I didn’t remember the password, and when I tried the password reset it said it didn’t recognize the email address, but when I tried to create an account using that same email address it said the user already existed.
I have now retrieved my password from Google and can log in from my tablet, but something is decidedly weird about your system.