Why is a field empty in my message? Pro
This feature is part of the Pro plan.
Because the student has no data for that field. For example they have no contact person, no pass with an expiry date, or the owed amount cannot be calculated because the pass has no unit price. Before sending, a red notice lists the empty fields: add the missing data, or remove the field from the text.
If the field name went out literally, in curly brackets, it was mistyped. A field like that stays uncoloured in the editor. Delete it and add it again with Insert field. If the student owes nothing, the 0 is not an error.