Youtube has stopped working

I’m not sure when this happened - but maybe when I installed the Amazon VOD add-on, youtube won’t start. I’m on Kodi 18 and this I think is the relevant part from the log:

14:31:25.941 T:4072031792 WARNING: CGUIMediaWindow::OnMessage - updating in progress
14:31:26.144 T:3233919728 ERROR: EXCEPTION Thrown (PythonToCppException) : -->Python callback/script returned the following error<–
- NOTE: IGNORING THIS CAN LEAD TO MEMORY LEAKS!
Error Type: <type ‘exceptions.ImportError’>
Error Contents: cannot import name python_2_unicode_compatible
Traceback (most recent call last):
File “/home/osmc/.kodi/addons/plugin.video.youtube/resources/lib/startup.py”, line 6, in
from youtube_plugin.kodion.impl import Context
File “/home/osmc/.kodi/addons/plugin.video.youtube/resources/lib/youtube_plugin/kodion/init.py”, line 12, in
from .abstract_provider import AbstractProvider
File “/home/osmc/.kodi/addons/plugin.video.youtube/resources/lib/youtube_plugin/kodion/abstract_provider.py”, line 4, in
from . import items
File “/home/osmc/.kodi/addons/plugin.video.youtube/resources/lib/youtube_plugin/kodion/items/init.py”, line 5, in
from .utils import to_json, from_json, to_jsons
File “/home/osmc/.kodi/addons/plugin.video.youtube/resources/lib/youtube_plugin/kodion/items/utils.py”, line 8, in
from .video_item import VideoItem
File “/home/osmc/.kodi/addons/plugin.video.youtube/resources/lib/youtube_plugin/kodion/items/video_item.py”, line 4, in
from .base_item import BaseItem
File “/home/osmc/.kodi/addons/plugin.video.youtube/resources/lib/youtube_plugin/kodion/items/base_item.py”, line 1, in
from six import python_2_unicode_compatible
ImportError: cannot import name python_2_unicode_compatible
–>End of Python script error report<–

Any help much appreciated.

First, seek support from the add-on developer.