[exactus]

Thanks for responses so far. I am trying to register a fastmail.com account using the Gmail app supplied on a friends samsung phone.

I have done this successfully on my own samsung and when I receive email to my FM account it is accessed via the Gmail icon. When I reply it uses my FM user name. (I'm only using the Gmail app because the fastmail app keeps on telling me it's trying to get to the server.)

So I am trying to use the same config from my phone to my friend's phone. But I suspect they may be different versions of the app.

(One mistake I did make was to use a new app password rather than the existing app password created for a tablet some months ago. But reverting to the existing app password hasn't helped.)