FTM has suddenly decided that it doesnt like me trying to sign-in to Ancestry.

When I try to go on-line, I am prompted to enter my Ancestry user details and password - which it then rejects with the answer "Login Failed Please Try Again".

I have ensured that I am using the same name and password - even to the point of logging out of Ancestry and logging in there again successfully.

I am using Windows 8.1 - nothing has changed on my PC since my last successful login about 2 weeks ago.

Any thoughts?