Cannot login on fire stick

Hello Ginapenoncello,

Thanks for choosing the Apple Support Communities. To start, have you tried logging in to the Apple ID website to ensure your credentials are correct? That can be checked using an internet browser here:

Manage your Apple ID

If they are correct, let's try these steps and see if they help.

Watch on Smart TVs and streaming devices - Apple Support

"Amazon Fire TV doesn’t support purchases within the Apple TV app, but when you sign in with your Apple ID, you can find everything you purchased, rented, or subscribed to using the same Apple ID on other devices.

1. On your Amazon Fire TV home screen, select Search.
2. Search for “Apple TV” or use Alexa and say “Apple TV app” as your search query. 
3. Select the Apple TV app  in Apps & Games, then select Get.
4. When downloaded, the Apple TV app appears in the Apps & Channels section of the home screen.
5. Select the Apple TV app to open it, then sign in with an Apple ID if prompted.
6. Note: If you don’t already have an Apple ID, you can create one on the Apple ID website. You need only one Apple ID to use Apple TV app services. For more information, see the Apple ID FAQ.

Optionally, you can go to the Apple TV App in Amazon.com and sign in to your account, follow the onscreen instructions to select the Amazon Fire TV device on which you want the app installed, then select Deliver.

For a list of specific models that support the Apple TV app, go to apple.com/apple-tv-app/devices/."

We hope this helps.

Cheers!