Hi there! I see you're facing an authorization failure with the Power Sync app on your iPhone. To get started, could you tell me a bit more about what happens when you try to authorize? For example, do you get any specific error message, or does the app fail silently? Also, have you recently changed any settings like your Fitbit or Apple Health credentials?

Meanwhile, here’s a step-by-step approach we can try to resolve the authorization failure on your iOS 18.7 device:

1. Log Out and Log Back In
Open the Power Sync app, log out of your Fitbit or any connected account, then log back in. This often refreshes the authorization token and fixes common issues.

2. Check Redirect URI Settings (if applicable)
Some authorization errors occur because the app’s redirect URI is outdated or incorrect. For instance, updating the redirect URI from something like FitbitHealthKitConnector:// to FitbitHealthKitConnector://params has resolved similar errors before.

3. Verify Permissions in Apple Health
On your iPhone, open the Apple Health app, tap your profile picture, then go to Apps > Power Sync. Make sure that the Power Sync app has the necessary permissions enabled to read and write health data.

4. Ensure Background App Refresh is Enabled
Go to your iPhone’s Settings > General > Background App Refresh, and ensure that it’s enabled for Power Sync.

5. Check for App Updates
Visit the App Store and confirm that you have the latest version of Power Sync installed to avoid compatibility issues.

6. Restart Your iPhone
Sometimes a simple restart can resolve temporary glitches related to apps and network connections.

If after these steps, the issue remains, I can guide you through more detailed diagnostic tools that Power Sync offers, such as the Sync Diagnostics Client, or help check if there are any reported server-side problems affecting authorization.

Could you let me know which steps you’ve already tried, or if you see any specific error codes or messages during authorization? That will help me assist you better!