Hi there! I see you're having trouble with the IBO Player showing your MAC address but not the device key. It's great that it worked once before, but let’s try to troubleshoot this together.

1. Restart Your Device: Sometimes, a simple restart can help refresh the system. Please go ahead and reboot your Mac and see if the IBO Player shows the device key afterwards.

2. Check for Updates: Make sure IBO Player is up to date. You can check for updates by going to the app store and looking for any available updates for IBO Player. Updating the app can often resolve issues.

3. Clear the App Cache: Occasionally, cached data can cause problems. To clear the cache for IBO Player:
- Open Finder.
- Click on Go in the menu bar, then select Go to Folder.
- Type ~/Library/Caches and press Enter.
- Find the folder for IBO Player and delete it.
- Restart the app afterwards.

4. Re-enter MAC Address: If there’s an option within the app settings, try re-entering your MAC address which could prompt the device key to appear again.

5. Reset the App: If none of the above steps work, you might consider uninstalling and reinstalling the IBO Player app. This will ensure that you’re starting fresh.

If you've tried these steps and still don’t see the device key, let me know, and we can explore deeper options or escalate to higher support. Are you satisfied with the solution I provided, or do you need further assistance?