Here is the log. Thank you for the help.
Spoiler:
calibre Debug log
calibre 4.15 embedded-python: True is64bit: True
Darwin-18.7.0-x86_64-i386-64bit Darwin ('64bit', '')
('Darwin', '18.7.0', 'Darwin Kernel Version 18.7.0: Sat Oct 12 00:02:19 PDT 2019; root:xnu-4903.278.12~1/RELEASE_X86_64')
Python 2.7.16
OSX: ('10.14.6', ('', '', ''), 'x86_64')
Interface language: None
Successfully initialized third party plugins: Gather KFX-ZIP (from KFX Input) (1, 31, 0) && DeDRM (6, 6, 3) && Package KFX (from KFX Input) (1, 31, 0) && KFX metadata reader (from KFX Input) (1, 31, 0) && KFX Input (1, 31, 0) && Obok DeDRM (6, 5, 4) && Count Pages (1, 9, 0) && Generate Cover (1, 5, 22)
calibre 4.15 embedded-python: True is64bit: True
Darwin-18.7.0-x86_64-i386-64bit Darwin ('64bit', '')
('Darwin', '18.7.0', 'Darwin Kernel Version 18.7.0: Sat Oct 12 00:02:19 PDT 2019; root:xnu-4903.278.12~1/RELEASE_X86_64')
Python 2.7.16
OSX: ('10.14.6', ('', '', ''), 'x86_64')
Interface language: None
Successfully initialized third party plugins: Gather KFX-ZIP (from KFX Input) (1, 31, 0) && DeDRM (6, 6, 3) && Package KFX (from KFX Input) (1, 31, 0) && KFX metadata reader (from KFX Input) (1, 31, 0) && KFX Input (1, 31, 0) && Obok DeDRM (6, 5, 4) && Count Pages (1, 9, 0) && Generate Cover (1, 5, 22)
devicePixelRatio: 2.0
logicalDpi: 72.0 x 72.0
physicalDpi: 110.50000166 x 110.50000166
Using calibre Qt style: True
[0.00] Starting up...
[0.02] Showing splash screen...
[0.31] splash screen shown
[0.31] Initializing db...
[0.42] db initialized
[0.42] Constructing main UI...
DEBUG: 0.0 obok::utilities.py - loading translations
DEBUG: 0.0 obok::dialogs.py - loading translations
DEBUG: 0.0 obok::config.py - loading translations
DEBUG: 0.0 obok::action_err.py - loading translations
[1.70] main UI initialized...
[1.70] Hiding splash screen
qt.qpa.fonts: Populating font family aliases took 1496 ms. Replace uses of missing font family "Sansserif" with one that exists to avoid this cost.
QImage::scaled: Image is a null image
calibre 4.15 embedded-python: True is64bit: True
Darwin-18.7.0-x86_64-i386-64bit Darwin ('64bit', '')
('Darwin', '18.7.0', 'Darwin Kernel Version 18.7.0: Sat Oct 12 00:02:19 PDT 2019; root:xnu-4903.278.12~1/RELEASE_X86_64')
Python 2.7.16
OSX: ('10.14.6', ('', '', ''), 'x86_64')
Interface language: None
Successfully initialized third party plugins: Gather KFX-ZIP (from KFX Input) (1, 31, 0) && DeDRM (6, 6, 3) && Package KFX (from KFX Input) (1, 31, 0) && KFX metadata reader (from KFX Input) (1, 31, 0) && KFX Input (1, 31, 0) && Obok DeDRM (6, 5, 4) && Count Pages (1, 9, 0) && Generate Cover (1, 5, 22)
Traceback (most recent call last):
File "calibre_plugins.generate_cover.action", line 66, in _generate_cover
File "calibre_plugins.generate_cover.dialogs", line 1379, in __init__
File "calibre_plugins.generate_cover.dialogs", line 1671, in display_preview
File "calibre_plugins.generate_cover.draw", line 331, in generate_cover_for_book
File "calibre_plugins.generate_cover.draw", line 179, in create_cover_page
File "site-packages/calibre/utils/magick/legacy.py", line 111, in compose
ValueError: left and/or top out of bounds
[10.02] splash screen hidden
[10.02] Started up in 10.02 seconds with 2509 books