Step 1 - Go to the website,, and click on forgot password.

Step 2 - When you receive the temporary password it is best to type it in (copy/paste sometimes picks up extra characters making the password wrong).

Step 3- Once you have reset your password on the website, go back to the app.  

Click on Reset or Remove PIN then click the Continue to login button.

Step 4 - Enter your email address and new password, click on Remember my Details and set your PIN again.