The app may not be accepting your password for one of a few reasons. The most common reason is because there are 2 ways to subscribe to the app: directly through https://subscriptions.independent.co.uk/, or through the App Store on your device.
If you are subscribed directly through iTunes, Google Play or Amazon Kindle you can reset your password by visiting the following websites:
Apple iTunes: http://iforgot.apple.com
Google Play: https://www.google.com/accounts/ForgotPasswd
If you are subscribed through Independent Subscriptions you can reset your password by opening https://subscriptions.independent.co.uk/forgot-password in a web browser, then enter your email address. You will then be sent a message that contains a link to reset your password.
If you have subscribed directly through us, you can reset your password using this link: https://subscriptions.independent.co.uk/forgot-password