App.run fails on "FileNotFoundError"

[2023-06-06 13:26:27 +0000] [1] [ERROR] Experienced exception while trying to serve
Traceback (most recent call last):
[2023-06-06 13:26:27 +0000] [1] [INFO] Server Stopped
  File "/usr/local/lib/python3.10/site-packages/sanic/mixins/startup.py", line 764, in serve
    worker_state: Dict[str, Any] = sync_manager.dict()
  File "/usr/local/lib/python3.10/multiprocessing/managers.py", line 723, in temp
    token, exp = self._create(typeid, *args, **kwds)
  File "/usr/local/lib/python3.10/multiprocessing/managers.py", line 606, in _create
    conn = self._Client(self._address, authkey=self._authkey)
  File "/usr/local/lib/python3.10/multiprocessing/connection.py", line 502, in Client
    c = SocketClient(address)
  File "/usr/local/lib/python3.10/multiprocessing/connection.py", line 630, in SocketClient
    s.connect(address)
FileNotFoundError: [Errno 2] No such file or directory
Traceback (most recent call last):
  File "/app/app.py", line 256, in <module>
    app.run(host='0.0.0.0',
  File "/usr/local/lib/python3.10/site-packages/sanic/mixins/startup.py", line 207, in run
    serve(primary=self)  # type: ignore
  File "/usr/local/lib/python3.10/site-packages/sanic/mixins/startup.py", line 764, in serve
    worker_state: Dict[str, Any] = sync_manager.dict()
  File "/usr/local/lib/python3.10/multiprocessing/managers.py", line 723, in temp
    token, exp = self._create(typeid, *args, **kwds)
  File "/usr/local/lib/python3.10/multiprocessing/managers.py", line 606, in _create
    conn = self._Client(self._address, authkey=self._authkey)
  File "/usr/local/lib/python3.10/multiprocessing/connection.py", line 502, in Client
    c = SocketClient(address)
  File "/usr/local/lib/python3.10/multiprocessing/connection.py", line 630, in SocketClient
    s.connect(address)
FileNotFoundError: [Errno 2] No such file or directory

From the stack trace it looks to me like connecting to a Multiprocessing unix-socket fails?

how are you trying to run it?