Can’t authorise ie login to ADE on my iPad

I hope someone has an answer. 

I simply can't login/authorise ADE under the adobe ID, despite having an Adobe ID, ie email, and a valid password. 
I've confirmed the password is ok, ie logging into this forum for instance. 
l've tried several times and get the same error, username or password incorrect. 
As I say, I hope someone can suggest a solution.