Why would an Automated Card Button I created to clear checklists stop working?

Ben Stevens_z5kpj0

I created an automated button which was copied onto every card to clear checklists at the end of the week. This was working fine for a while and then stopped and I now get a 'Butler Button Error'?  I have tried to find the root cause to no avail.  I have also tried to delete and recreate the button but I am unable to delete or edit it as it is greyed out?

I have also added a new card and it does not appear at all!?

 

Ben Stevens_z5kpj0

I found the answer - I must have added the card when I was a member of the workspace and had somehow been detached from it.  On relinking to the workspace, the button worked again 👍