Got this error message when trying an image occlusion add-on. It was working perfectly fine yesterday

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.
When you’ve discovered the add-on that is causing the problem, please report the issue on the add-on support site.
Debug info:
Anki 2.1.43 (0fbae6bc) Python 3.8.6 Qt 5.14.2 PyQt 5.14.2
Platform: Windows 10
Flags: frz=True ao=True sv=2
Add-ons, last update check: 2021-08-02 10:58:32

Caught exception:
Traceback (most recent call last):
File “aqt\webview.py”, line 526, in handler
File “C:\Users\20oma\AppData\Roaming\Anki2\addons21\1374772155\add.py”, line 278, in
lambda val, choice=choice, close=close: self._onAddNotesButton(choice, close, val))
File “C:\Users\20oma\AppData\Roaming\Anki2\addons21\1374772155\add.py”, line 293, in _onAddNotesButton
r = gen.generateNotes()
File “C:\Users\20oma\AppData\Roaming\Anki2\addons21\1374772155\ngen.py”, line 80, in generateNotes
(svg_node, layer_node) = self._getMnodesAndSetIds()
File “C:\Users\20oma\AppData\Roaming\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’