Hi! I understand you're seeing a "system unavailable" message when trying to log into the MyGEHA app on your Mac running OS X 10.15.7. Let's work together to get this sorted out.

First, just to clarify, are you trying to log in through a web browser on your Mac, or are you using a dedicated MyGEHA app? If it's a browser, which one are you using (Safari, Chrome, etc.)? Also, have you tried accessing the site from another device or network to rule out connectivity issues?

In the meantime, here are some steps that often help with this type of message:

1. Check Internet connection: Make sure your Mac is properly connected to the internet by loading other websites.
2. Clear browser cache: Sometimes old files in your browser cache cause errors. On Safari, go to Safari > Preferences > Privacy > Manage Website Data > Remove all.
3. Try a different browser: If you're on Safari, try Chrome or Firefox to see if the error persists.
4. Restart your Mac: A quick reboot can resolve temporary glitches.
5. Check MyGEHA status: Sometimes the “system unavailable” message means the MyGEHA servers or services are down for maintenance. You can visit MyGEHA’s official social media or status pages for updates.

If after these steps you still see the message, please let me know exactly what you’ve tried and any additional details you observe (like error codes or how long this has been happening). That will help me guide you further.

Are you currently seeing this issue only on your Mac, or on other devices as well?