Fedora Account System
Red Hat Associate
Red Hat Customer
From Extensions/Todoist/Settings dialog click "Add a todoist account" button. It opens Online accounts settings page but there is no Todoist account type to add there so nothing can be done and the extension can't be used.
Changing to gnome-online-accounts as my investigation points me in the direction that goa doesn't ship the todoist integration.
*** This bug has been marked as a duplicate of bug 1510239 ***