If you experience the error code F7121-5006 on your computer, often accompanied by the following message:
Sorry, too many people are watching on your account right now.
Your Netflix account has reached the maximum number of active streams. Follow the troubleshooting steps below to resolve the issue.
If you have the Netflix player open in any other browsers or tabs, your computer may be counting each browser as a device.
To solve the problem, close any other browser tabs playing Netflix on this computer and play your movie or TV show again.
If you've shared your Netflix account with friends or family, they may be using Netflix while you're trying to watch a movie or TV show. The number of users that can stream at the same time will depend on your Netflix plan. You can see the limit for your account, as well as other plan options, from the Change Plan page.
To solve this problem, make sure that no one else is using your account before trying to stream again.
If you're not sure what other device was streaming, check your recent Viewing Activity. If you see anything you don't recognize, follow the steps in Someone is using my Netflix account without my permission.
Sometimes the Netflix app thinks it's still playing something even though it's not.
To solve this problem, try again later. The error message will go away on its own, but it may take up 2 hours.