Trello cards have an email address associated with them, and for a long time I have been able to email files to cards. The file attached to the email became a file attached to the card. In the last few days, this seems to have stopped working.
What happened? How can I restore this behavior?
Note that the subject line of the email does come through as a comment on the card, so the email is being received and processed. This is across multiple boards.