Me too. Pixel 4 running Android 10. With Beta 1.4 the app was unable to find my phone’s number on my account. Updating to 1.5 fixed that and allowed me to complete logging in.
Now I’m stuck trying to set Jolly Roger as my incoming call handler. Apps -> Default Apps -> Phone App, and Caller ID & Spam App, neither setting includes Jolly Roger as a selectable option.