The login works on the app but not online

for some reason a while ago I created a musescore account on my iPad(in the app). I used it for a few months then decided it would be good if I could use it online too. I knew my login and put in the login details, it then came up saying it was wrong. then I used my iPhone and the musescore app to try and slowly put in the passwords I sometimes used on different accounts(not associated with musescore) I then used my login details which I had already used to log in online and it worked. I did try this on another account I created and this one to post the issue.
To try this yourself

1) download the musescore app and create a new account with your email(not apple, google or facebook) also note down your password.

2)open a browser and then come to musescore then click login and type in your new account username and password.