Hi there! I see you're having trouble opening the Paperless Post app. Let's get this sorted out together.

First, could you please confirm if you're trying to open Paperless Post through a web browser on your Windows 10 device or using a separate app? Also, is there any error message showing up when you try to open it? Any extra detail will help me assist you better.

In the meantime, here are some initial steps that often resolve opening issues on Paperless Post:

1. Update your browser: Since you mentioned WebKit, it sounds like you might be using a browser built on WebKit engine (like Safari variants or others). Make sure your browser is updated to the latest version, as old versions may have compatibility issues.

2. Clear cache and cookies: Sometimes cached data causes trouble in loading apps. Go to your browser settings, find the option to clear browsing data, and clear cache and cookies.

3. Restart your browser or device: A fresh start can refresh system resources and clear temporary glitches.

4. Disable browser extensions temporarily: Some browser add-ons can interfere with website functionality.

If you've tried any of these already, just let me know which ones, and I’ll guide you further.

Also, it’s good to verify if Paperless Post itself is having any service issues. You can check their status at their official status page.

Would you like me to walk you through these steps or check for more specific solutions based on what you've tried so far?