It's possible that the HP Sprocket App does not have sufficient permissions to access the Photos app. I believe we can grant full permissions for the app from the iOS settings. Let's try these steps;
1.) Open Settings on your iOS device.
2.) Scroll all the way down unit you see HP Sprocket.
3.) Touch Sprocket, then touch Photos and enable Read/Write permissions and also make sure that Camera and Save Camera Photos are enabled.
Let me know how it goes!
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Have a great day!