password not recognized when signing into iphone but works on notebook pc.

Dear Forum users,

I am finding it difficult to use my password for adobe acrobat reader on the iphone as it prompts me to sign in with my user and pass plus phone number. 

All is fine except my password which is not recognised on the iphone but recognised on the notebook pc.

Can anyone advise what steps I can take to remediate the issue? 

Please help.

Sincerely,

Zarique