If you don't know your password, or suspect you are using the wrong password you will find a Forgot Password button in the app. This will email the current registered password to you and you will not be forced to reset it. To locate this button, go to the User Account and type your email address into the Login screen and a blue Forgot Password button will appear. Press this.
If you wish to change your Password or Security Key (for tracking) use the Manage Account button. This will take you to the website, and open your Account. Click Account Details where you will be able to edit and save changes. You can even delete your Account here.
If you believe you have the correct combination of email address and password but are still having problems logging into the app - use the backspace delete method to remove any auto-filled details from the login screen and manually type each character of your email address and password into the login screen.