A warm welcome from me too.

In terms of your sign in issues, when was the last time you signed in to ba.com? If it was a while ago there have been some changes and you are supposed to use your email now as your username rather than your membership number. There was also an issue a few years ago where we had to all reset our passwords and change them to stronger ones. If you are using the right username is it just a reset password you need to try?