In order to enable cookies on Amazon Prime Video, you will need to change the settings in your browser. Here are the steps:
1. Open your preferred browser and go to the Amazon Prime Video website.
2. Click on the menu icon in the top right corner and select Settings.
3. Under the Privacy section, click on the Cookies tab.
4. Make sure that the Accept Cookies option is turned on. If it isn't, click on it to turn it on.
5. Close the Settings window and you should now be able to watch videos on Amazon Prime Video without any issues.