Missing cookie session-id

[CosaroLisa]

Hello,
I'm using this library to implement some tool to be integrated in Blackboard.
I'm often getting this exception:

[2024-12-18 11:46:32 +0000] [9] [ERROR] Error handling request /launch/
web-1    | Traceback (most recent call last):
web-1    |   File "/usr/local/lib/python3.9/site-packages/gunicorn/workers/gthread.py", line 281, in handle
web-1    |     keepalive = self.handle_request(req, conn)
web-1    |   File "/usr/local/lib/python3.9/site-packages/gunicorn/workers/gthread.py", line 333, in handle_request
web-1    |     respiter = self.wsgi(environ, resp.start_response)
web-1    |   File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 1498, in __call__
web-1    |     return self.wsgi_app(environ, start_response)
web-1    |   File "/app/app.py", line 50, in __call__
web-1    |     return self.app(environ, start_response)
web-1    |   File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 1476, in wsgi_app
web-1    |     response = self.handle_exception(e)
web-1    |   File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 1473, in wsgi_app
web-1    |     response = self.full_dispatch_request()
web-1    |   File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 882, in full_dispatch_request
web-1    |     rv = self.handle_user_exception(e)
web-1    |   File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 880, in full_dispatch_request
web-1    |     rv = self.dispatch_request()
web-1    |   File "/usr/local/lib/python3.9/site-packages/flask/app.py", line 865, in dispatch_request
web-1    |     return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)  # type: ignore[no-any-return]
web-1    |   File "/app/app.py", line 250, in launch
web-1    |     message_launch = ExtendedFlaskMessageLaunch(flask_request, tool_conf, launch_data_storage=launch_data_storage)
web-1    |   File "/usr/local/lib/python3.9/site-packages/pylti1p3/contrib/flask/message_launch.py", line 22, in __init__
web-1    |     super().__init__(
web-1    |   File "/usr/local/lib/python3.9/site-packages/pylti1p3/message_launch.py", line 236, in __init__
web-1    |     self.set_launch_data_storage(launch_data_storage)
web-1    |   File "/usr/local/lib/python3.9/site-packages/pylti1p3/message_launch.py", line 778, in set_launch_data_storage
web-1    |     raise LtiException(f"Missing %s cookie {session_cookie_name}")
web-1    | pylti1p3.exception.LtiException: Missing %s cookie session-id

. Can anyone help me with this ?