Doesn't work from an android phone using firefox, since the new webmail loaded.
Works ok from a laptop.
Rather than accessing via a browser on your phone I would recommend using an Android Mail app - Blue Mail works very well for me on Android. This bypasses the Web Mail interface. There have been problems with the new version of Firefox I know, to do with a new set-up and some clashes (though this is a PC not an Android report) - either which way using as few 'intermediaries' as possible seems a good idea. The apps address the BT mail servers directly, your route uses Firefox and then BT Web mail to get to the BT servers.