I have the same issue currently. Came to Sonarr to see why there's no new stuff in Kodi and all downloads were downloaded, but imported to Sonarr/Kodi.
Here is a error message from Sonarr:
Using the latest Milhouse build. I guess it's Libreelec 9.8 (?).
Rolled back to 9.1 and now seems to work again
EDIT: not working. Smae error