Hi there! I understand your EcoFlow device is no longer connecting to the app on your Mac, and I'd be happy to help you get that sorted out. To start, could you tell me a bit more about what exactly happens when you try to connect? For example:

- Are you unable to see your EcoFlow device listed in the app at all?
- Are you connecting via Wi-Fi or Bluetooth?
- Have you recently updated the app or your EcoFlow device's firmware?
- Is your Mac connected to the same Wi-Fi network that your EcoFlow device uses?
- Have you tried restarting the app or the device?

With those details, I can guide you through some simple steps to try and fix this. Meanwhile, here are some initial troubleshooting actions that usually help:

1. Restart devices and app: Close the EcoFlow app completely on your Mac, then restart your Mac and your EcoFlow device by turning it off and on again.

2. Check Wi-Fi connection: Make sure your Mac is connected to the same Wi-Fi network your EcoFlow device uses. Some EcoFlow devices create their own Wi-Fi hotspots—if that's the case, try connecting your Mac to that hotspot manually via the Wi-Fi menu.

3. Turn off 5 GHz Wi-Fi temporarily: EcoFlow devices sometimes have trouble connecting if your network uses 5 GHz Wi-Fi. If your router supports dual-band, try disabling the 5 GHz band temporarily and see if the connection succeeds on the 2.4 GHz band.

4. Update app and device firmware: Check that you have the latest version of the EcoFlow app installed from the official source. Also, if the device can be updated via the app or manually, make sure the firmware is current.

5. Reset Bluetooth and Wi-Fi on device: Some EcoFlow models allow you to reset their connectivity by powering off outputs, disconnecting inputs, then holding down the power button for a few seconds to reboot network components.

Please let me know which of these you've tried or if you need step-by-step help with any, and share any additional info you have. That way, I can tailor the guidance specifically for your Mac OS X 10.15.7 and EcoFlow device setup.

Looking forward to helping you reconnect smoothly!