So, further to my last post, I've now managed to log in. I was able to log in to my Microsoft account, and from there I went into the settings and clicked on 'View and Manage Account Data'. Althoug...
I have the same problem too with my new Galaxy Note 9. Had a OnePlus 6 previously, with no issues so it appears to be a recent thing. Running all the latest software, Android 9 and up to date app.