Hi there! I see you're encountering the error "beatXLevel.join.failed.generic" in the Time Blast app on your Mac running OS X 10.15.7. I want to clarify a bit so I can help you better:

- Are you trying to join a game level, tournament, or multiplayer session?
- Did this error pop up after a specific action, like updating the app or trying to connect to a server?
- Have you already tried anything like restarting the app or checking for updates?

Generally, the "join failed" generic error can happen due to version mismatches, connectivity issues, or account sync problems. Let's try a few steps to troubleshoot:

1. Check for App Updates:
Since version mismatch is a common cause, ensure your Time Blast app is updated to the latest version in the Mac App Store.

2. Log Into Your Account:
If the app allows login in settings, make sure you are logged in. This can help sync data and permissions properly.

3. Restart the App and Device:
Quit the app entirely, then relaunch it. If that doesn't help, restart your Mac to clear temporary glitches.

4. Check Internet Connection:
Make sure your network is stable. Try switching between Wi-Fi and wired if possible.

5. Clear Cache or Data (if applicable):
If the app offers a way to clear cache or reset settings without deleting important data, do that next.

6. Reinstall the App:
If all else fails, uninstall and reinstall the app to ensure all files are intact and fresh.

Could you tell me if you have the latest app version and if you are logged in? Also, any details about when the error occurs would help me guide you better.