error when importing transcription from Transkribus

(ENV) kermorvant@arius tasks % python3 arkindex_tasks/import_transkribus.py 64911 --corpus cfd4f8bc-dfd3-4048-b132-32fd753ea1e8 --folder-type folder
[INFO] Logged as kermorvant@teklia.com #4231
[INFO] Creating Folder Transkribus Test
[INFO] Fetching image for page 14398376
[INFO] Creating image for page 14398376
[INFO] Validating image 88209f03-af27-4acf-b9fb-23f92b06c852
[INFO] Creating page 14398376
[INFO] Importing transcript 27539457 to page ea3394b1-868d-4415-8674-d83412c795ca
Traceback (most recent call last):
  File "arkindex_tasks/import_transkribus.py", line 391, in <module>
    main()
  File "arkindex_tasks/import_transkribus.py", line 387, in main
    TranskribusImporter(**args).run()
  File "arkindex_tasks/import_transkribus.py", line 337, in run
    line_type=self.line_type,
  File "arkindex_tasks/import_transkribus.py", line 209, in run
    line_type=self.line_type,
  File "arkindex_tasks/import_transkribus.py", line 139, in run
    self.upload_transcriptions()
  File "arkindex_tasks/import_transkribus.py", line 107, in upload_transcriptions
    parser.save(self.page, self.paragraph_type, self.line_type)
  File "/Users/kermorvant/Work/Arkindex/tasks/arkindex_tasks/pagexml.py", line 75, in save
    region, element, region_count, paragraph_type
  File "/Users/kermorvant/Work/Arkindex/tasks/arkindex_tasks/pagexml.py", line 50, in create_element
    "image": parent["zone"]["image"]["id"],
TypeError: 'NoneType' object is not subscriptable