Hi there! I understand you're having trouble with the Hallmark+ app showing an "unable to play" message when you try to resume watching "Haul Out the Halloween." Let's work through this together.

First, to get a clearer picture, could you tell me if this issue happens only with this specific title or with other videos too? Also, have you tried any steps already like restarting the app or your Mac?

Meanwhile, here are some initial steps we can try on your Mac running OS X 10.15.7:

1. Restart the Hallmark+ app: Quit the app completely (Command + Q), then relaunch it and try playing the video again.

2. Check your internet connection: A weak or unstable network can cause playback issues. Ensure your Wi-Fi or Ethernet is stable. You can try restarting your router if needed.

3. Log out and back in: Sometimes, refreshing your account session helps. In the app, log out of your Hallmark+ account, then log back in.

4. Clear app cache or data: On Mac, this might involve deleting temporary files related to the app—though this is less straightforward, we can check for any stored data inside the app preferences.

5. Restart your Mac: Sometimes, a simple restart clears temporary glitches.

Try these and let me know if the issue persists or if you see any other messages or behaviors. That will help me guide you further!