The account you have created on mykronoz.com and the one you have created via the MyKronoz App (or any other app from MyKronoz) are not the same and are not linked.
Thus, you will not be able to log in the MyKronoz app using the same credentials of the webshop.
You will have to create a new account on the app.
Note: resetting the password in the MyKronoz App will not reset the password from the webshop and vice-versa.