Unable to log in on mobile app

If I try to log in on the mobile app, I get the message "Sorry - request aborted". I'm using a Galaxy S6, running Android 7.0.

I've tried reinstalling the app (most recently today) without success.

Can you suggest any way to deal with this? I loved using the mobile app, and it would be great to be able to use it again.

Thanks

Richard Moyse