@Ondřej-Šutera I have updated the app. I have verified that the email and the password are exactly the same. Even my Apple ID/store email is the same. I am trying this while sitting in front of my computer so there is no guesswork. What could be the problem? I do not have an alternate email to use for one app/subscription.
Thank you.

@Ondřej-Šutera I am having the same problem but I do not see how to "assign the premium to an account". Purchased the subscription on my desktop but cannot access it on my iOS device. Error returned is "Wrong email/password".