I
am the developer of
Powerwall Companion. The issue where a minority of people couldn't sign in had plagued me for a while since I couldn't ever reproduce it, but I
think I've finally resolved this in the latest version (2.1.0.0). I've also provided a new option for the app to pull the data from the gateway on your local network if you don't want to use your Tesla credentials, although when using this option the app is a bit more limited.
@ssq could you please try the latest version of the app and let me know if it's working for you now?