Error message: "Too many simultaneous streams".
The number of simultaneous streams per HBO GO account is limited for security reasons. The username and password that you sign in with shouldn't be shared with anyone outside of your household. If you share your sign-in information, you might not be able to watch videos because too many people are using your profile at the same time.
If you're getting a "too many simultaneous streams" error message, have everyone in your household sign out of HBO GO (go to Settings > Sign Out), then restart their devices. Then sign back in and try playing a video.
If you're still getting the error...
If you think that there are people using your HBO GO account on devices you don’t own, you should change your password immediately and contact HBO GO customer support if the error persists.