As of Sept 5, 2019, direct integration with Todoist in Drafts is not working.
It appears that Todoist had deprecated the API endpoint used by Drafts integration, and we were not aware of the pending change. Todoist shut down operation of those deprecated endpoints sometime in the last 24 hours or so, causing Todoist actions in Drafts to return errors.
We are beta testing an update to address these changes and should have a fix out in the next update.
Actions which integrate with the Todoist app via URL schemes are still functional.
If you rely on these Todoist actions and would like access to the beta, please see information regarding the beta program in this post.