Based on the image you shared, this doesn’t seem to be a token issue.
The HTTP 422 Unprocessable Content client error response status code indicates that the server understood the content type of the request content, and the syntax of the request content was correct, but it was unable to process the contained instructions.
We’d need more logs to give a better explanation. In the meantime, I would advisable to contact Jellyfin support directly. They may be able to help faster because they know what their plugin is doing.