Hi there! I understand you're able to play back recordings on all your cameras except for one particular camera on the DMSS app on your phone. Let's try to figure out what might be causing this.

To start, could you tell me:
- Is this camera part of the same NVR/DVR system as the others?
- Have you recently updated the DMSS app or the camera's firmware?
- Does the live view for that specific camera work fine on your phone?
- Are you getting any error messages when trying to play back recordings from that camera?

Meanwhile, here is a general approach to troubleshooting this kind of playback issue on DMSS:

1. Check Firmware and App Versions
Make sure both your camera/NVR firmware and DMSS app are updated to the latest versions. Incompatibility between versions can cause playback problems.

2. Restart and Reconnect
Sometimes, removing the camera from the app and then adding it back helps refresh connections.

3. Verify Recording Availability
Confirm that the camera in question actually has recordings during the time period you are trying to play back. This can be checked on the NVR or through the web interface if available.

4. Check Network Connectivity
Ensure the problematic camera has stable network connectivity. Playback may fail if the camera cannot stream recorded data properly.

5. Clear Cache or Reinstall DMSS App
Sometimes app data can become corrupted. Clearing cache or reinstalling may resolve playback hiccups.

If after these you still can’t play back recordings specifically for that camera, it might be due to software bugs or timeline interface bugs within the app. Consider checking for app updates or rolling back to a previous stable version if the problem began after an update.

Let me know what you find or if you want guidance on any specific step! Are you satisfied with this initial direction?