Hi there! I understand that when you try to capture a receipt using the Upside app, the camera screen just shows a black screen and nothing is visible. Let's work together to get that camera working correctly for you.

First, could you tell me a bit more:
- Did the app's camera function ever work properly before, or is this a first-time issue?
- Have you checked if other apps on your WebKit browser can use the camera without issues?
- Have you tried restarting the app or your device yet?

While you answer that, here are some foundational steps tailored for your Windows 10 device and WebKit browser:

1. Check Camera Permissions:
Make sure the Upside app or the browser you’re using has permission to access your camera.
- Go to Windows Settings > Privacy > Camera.
- Ensure the toggle for "Allow apps to access your camera" is ON.
- Also, check if the browser you use supports camera access and has permission enabled.

2. Close and Reopen the App or Browser:
Sometimes, apps or browser instances can glitch on camera initialization. A full restart often fixes this.

3. Clear Cache and Cookies:
Since the Upside app is running in WebKit on your Windows 10, clearing browsing data might resolve this.
- Open the browser settings.
- Find the option to clear cache and cookies.
- Restart the browser and try again.

4. Check for Updates:
Make sure the Upside app or your browser is updated to the latest version. Updates often fix bugs that cause the black screen problem.

5. Lighting and Environment:
Ensure you are in a well-lit environment, and the camera lens is clean. Although this usually doesn't cause a black screen, it's good to check.

If you’ve tried these or the problem persists, we can dive into more advanced checks like:

- Testing the camera with other apps or websites to verify hardware functionality.
- Trying a different browser if possible, to isolate whether it's browser-related.
- Checking for any running background apps that might be locking the camera.

Let me know what you've tried and how things look on your end! This way, I can guide you smoothly to a fix.