Error when using any feature in image occulsion (except shapes))

Error
An error occurred. Please start Anki while holding down the shift key, which will temporarily disable the add-ons you have installed.
If the issue only occurs when add-ons are enabled, please use the Tools > Add-ons menu item to disable some add-ons and restart Anki, repeating until you discover the add-on that is causing the problem.
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Debug info:
Anki 2.1.33 (3f403040) Python 3.8.0 Qt 5.14.2 PyQt 5.14.2
Platform: Mac 10.14.6
Flags: frz=True ao=True sv=1
Add-ons, last update check: 2020-09-28 06:43:34
Add-ons possibly involved: ⁨Image Occlusion Enhanced for Anki 21 alpha⁩

Caught exception:
Traceback (most recent call last):
File “aqt/webview.py”, line 493, in handler
File “/Users/AlissaSonia/Library/Application Support/Anki2/addons21/1374772155/add.py”, line 278, in
lambda val, choice=choice, close=close: self._onAddNotesButton(choice, close, val))
File “/Users/AlissaSonia/Library/Application Support/Anki2/addons21/1374772155/add.py”, line 293, in _onAddNotesButton
r = gen.generateNotes()
File “/Users/AlissaSonia/Library/Application Support/Anki2/addons21/1374772155/ngen.py”, line 80, in generateNotes
(svg_node, layer_node) = self._getMnodesAndSetIds()
File “/Users/AlissaSonia/Library/Application Support/Anki2/addons21/1374772155/ngen.py”, line 190, in _getMnodesAndSetIds
mask_doc = minidom.parseString(self.new_svg.encode(‘utf-8’))
AttributeError: ‘NoneType’ object has no attribute ‘encode’