Covers error

After fetching metadata, I found that quite a few ebooks had wrong information. I wanted to strip all of this from all the ebooks (from Feedbooks and Standard Ebooks). I selected "Set metadata (except cover) from the e-book files" and the cover "Set from e-book files". I get the following error:

calibre, version 7.9.0
ERROR: Failed: Failed to export image as JPEG with error: Image is empty

Traceback (most recent call last):
File "calibre\gui2\dialogs\metadata_bulk.py", line 189, in do_it
File "calibre\gui2\dialogs\metadata_bulk.py", line 243, in do_all
File "calibre\gui2\dialogs\metadata_bulk.py", line 227, in read_file_metadata
File "calibre\db\cache.py", line 86, in call_func_with_lock
File "calibre\db\cache.py", line 1781, in set_cover
File "calibre\db\backend.py", line 1791, in set_cover
File "calibre\utils\img.py", line 302, in save_cover_data_to
File "calibre\utils\img.py", line 205, in image_to_data
ValueError: Failed to export image as JPEG with error: Image is empty

It doesn't tell me which ebooks are causing the error.