I had the same problem.
The Netflix addon is installed from the castagnaIT repo. I had this repo on my NAS and installed the repo & addon directly in kodi, not via the max2play repo installation function.
The error log reads as this:
2022-02-18 19:31:08.462 T:1630507232 ERROR: [plugin.video.netflix (0)] Background services do not start due to the following error
2022-02-18 19:31:08.476 T:1630507232 ERROR: [plugin.video.netflix (0)] Traceback (most recent call last):
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/run_service.py", line 68, in init_servers
self._init_server(server)
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/run_service.py", line 89, in _init_server
(self.HOST_ADDRESS, select_port(server['name']))
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/services/msl/http_server.py", line 95, in __init__
self.msl_handler = MSLHandler()
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/services/msl/msl_handler.py", line 76, in __init__
self._init_msl_handler()
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/services/msl/msl_handler.py", line 100, in _init_msl_handler
self.msl_requests = MSLRequests(msl_data)
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/services/msl/msl_requests.py", line 36, in __init__
super(MSLRequests, self).__init__()
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/services/msl/msl_request_builder.py", line 32, in __init__
from .default_crypto import DefaultMSLCrypto as MSLCrypto
File "/home/pi/.kodi/addons/plugin.video.netflix/resources/lib/services/msl/default_crypto.py", line 29, in <module>
from Crypto.Util import Padding
ImportError: cannot import name PaddingSolution: sudo apt install python-pycryptodome
