Hi there! I see you're having trouble getting the Signia App to open on your Mac running OS X 10.15.7. Let me help you get this sorted out.

First, could you tell me a bit more about what happens when you try to open the app? For example:
- Does the app give any error message, or does it just not respond?
- Have you been able to open it before on this Mac?
- Did you recently update either the app or the operating system?

While I wait for your details, here are some simple steps we can try:

1. Force Quit and Restart the App:
- Press Command + Option + Esc to open the Force Quit Applications window.
- If Signia App is listed there, select it and click Force Quit.
- Then try opening the app again from your Applications folder.

2. Restart Your Mac:
- Sometimes a fresh start clears temporary glitches.
- Click the Apple menu, choose Restart, and after reboot, try launching the app again.

3. Check Internet and Bluetooth:
- Ensure your Mac is connected to the internet, as the app may need to access online services.
- Even though this is a Mac, check if Bluetooth is enabled in System Preferences, as the app may use it for communication with hearing aids.

4. Update the Signia App:
- If you installed the app from the App Store, open App Store > Updates, and see if there is an update available.

If these steps don’t get the app to open, we can move on to more advanced troubleshooting such as clearing app cache or reinstalling the app.

Could you let me know if you’ve already tried any of these or if you see any messages when opening the app? That way, I can target the solution better for you.