• Connect to the internet or wifi: Prime Video requires a reliable internet connection to function. Prime Video can only be viewed if you are connected to the internet. Make sure your streaming device is connected to an internet connection, regardless of whether it's wifi or cellular. Reset your internet router if the Amazon Prime not working.

• Restart your device or reinstall the app: If restarting your device doesn't work, you can uninstall and reinstall the app. Restarting your device is possible if you have narrowed down the issue to one device. If this doesn't work, you can uninstall Prime Video and then reinstall it. After you have done this, you will need to log in again to Prime Video.

• Pause other internet activity and shut off unneeded network tools: Prime Video may slow down if other internet users are using the same connection. Your internet connection could be being used by other data. Prime Video may lose essential bandwidth if someone downloads large files or plays on the same Wi-Fi network.

• Stop all other internet activity from checking, and then try Prime Video again. You might also need to move your streaming device closer to your internet router if you use wifi. To ensure your connection is not slowed down, you should also turn off network tools such as a VPN.

• Try Prime Video on a different device: Prime Video should work on all devices except one. This will let you know which device is the problem. Try Prime Video on a different device if Prime Video doesn't work on your preferred device. For example, open the Prime Video app on your smartphone to see if it works on Roku or smart TVs. Or, you can open Prime Video on your computer. You've solved the problem if it works on one device and not on another. Reboot the device Prime Video isn't running on, and then try again.

• To watch all of the videos, make sure you have the correct HDMI cable: Although it is rare, it may be possible that your HDMI cable is not up-to-date or compatible if you are having difficulty watching Prime Video. You will need a cable that is HDCP 1.4 or higher to view HD content.

• A cable that is HDCP 2.0 HDMI compatible will be required for 4K content. If you don't have the original package or order details from an online purchase, you won't determine what kind of cable you have. You may need to check the cable for any markings. You can also buy a newer cable if your cable is old.

Sources: https://sites.google.com/view/amazon-video-prime1/