Version
3.28

Describe the bug
If a video is missing in the database, the cw block shows an error message, see screenshot.

To Reproduce
Steps to reproduce the behavior:

1. Go to Courseware
2. Create Opencast cw block with a video
3. Delete this video in the work place
4. See error

Expected behavior
The block should display a more precise message, e.g. like the message for a video marked for deletion:

Screenshots