Hi there! I understand you're having trouble opening the VINELink app on your Mac running OS X 10.15.6. Let's see if we can get that working for you.

First, could you tell me a bit more about what happens when you try to open the app? For example, does the app crash, fail to launch at all, or maybe show an error message? Also, did you download the app from the App Store, or are you trying to access VINELink through a web browser?

In the meantime, here are some general steps you can try to resolve app opening issues on your Mac:

1. Restart Your Mac: Sometimes a simple reboot clears up temporary glitches.

2. Update the App: If you have the VINELink app installed from the App Store, check if there is an update available. Open the App Store, go to Updates, and see if VINELink has one.

3. Check macOS Updates: Ensure your Mac's operating system is up to date. Go to the Apple menu > System Preferences > Software Update.

4. Clear App Cache or Reinstall the App:
- If the app opens but is buggy, you can try deleting it and reinstalling from the App Store.
- To delete, drag the VINELink app from Applications to the Trash, then reinstall it fresh.

5. Try Accessing VINELink via Web Browser: Since you're on a Mac, you might also try using a browser like Safari or Chrome to visit https://vinelink.dhs.gov directly. This can be a good alternative if the app isn't behaving properly.

Once I know a bit more about what you're seeing, I can guide you through more specific troubleshooting steps! Are you able to try any of these suggestions so far?