I correctly entered my Sky / Yahoo address as usual but told it needed updating. Following instructions presented me with the message that I was not recognised by either email or password. Having gone round in circles trying numerous suggestions I have finally decided to request your assistance.
I know a couple of people who use it regularly who have been unable to use sky email on their ipads today (was okay this morning but this afternoon it says their password is incorrect or user name isn't known.
I had a similar issue with sky email on my phone. I had to change my password. The new one worked for a few days but then wasn't recognised- so I tried the old password and that worked.
So I think there is a problem.