Cloze deletion can only be used in fields which use the 'cloze:' filter

Click “Cards…” to see the card templates. The front template should contain {{cloze:Text}}, but in your case it’s probably only {{Text}}. If you click “Save”, a similar error message should appear.
The cloze: is required to handle the cloze text correctly and replace {{c1::mangoes}} with [...] on the front and mangoes on the back.

4 Likes