If you purchased an add-on subscription to HISTORY Vault from Amazon Prime Channels, your subscription can only be viewed through the Amazon Prime Video apps. More information from Amazon on the Prime Video apps is here: https://www.amazon.com/gp/video/splash/getTheApp
Subscriptions purchased via a partner service like Prime Video cannot be used to log in to the HISTORY Vault website or apps. If you would prefer to be able to stream via our website or native apps, we recommend that you subscribe through our website at historyvault.com instead. (If you change billing platforms, please ensure you have cancelled your subscription via Prime Video before re-subscribing to avoid having multiple subscriptions.)